diff --git a/Number_types/include/CGAL/Exact_rational.h b/Number_types/include/CGAL/Exact_rational.h
index 613fa0cd0f0..f07c61d42a9 100644
--- a/Number_types/include/CGAL/Exact_rational.h
+++ b/Number_types/include/CGAL/Exact_rational.h
@@ -14,6 +14,9 @@
 //
 // Author(s)     : Laurent Rineau
 
+#ifndef CGAL_EXACT_RATIONAL_H
+#define CGAL_EXACT_RATIONAL_H
+
 #include <CGAL/Number_types/internal/Exact_type_selector.h>
 
 namespace CGAL {
@@ -44,3 +47,5 @@ typedef internal::Exact_field_selector<double>::Type Exact_rational;
 #endif
 
 } /* end namespace CGAL */
+
+#endif // CGAL_EXACT_RATIONAL_H
diff --git a/Number_types/include/CGAL/Mpzf.h b/Number_types/include/CGAL/Mpzf.h
index b1b023a1058..c2689f3ee45 100644
--- a/Number_types/include/CGAL/Mpzf.h
+++ b/Number_types/include/CGAL/Mpzf.h
@@ -10,12 +10,13 @@
 //
 // Author(s)        :  Marc Glisse
 
+#ifndef CGAL_MPZF_H
+#define CGAL_MPZF_H
+
 #ifndef CGAL_NO_MPZF_DIVISION_OPERATOR
 #define CGAL_MPZF_DIVISION_OPERATOR 1
 #endif
 
-#ifndef CGAL_MPZF_H
-#define CGAL_MPZF_H
 #include <cstdlib>
 #include <algorithm>
 #include <climits>
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/bbox.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/bbox.h
index 580dccecb52..a4d199871cb 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/bbox.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/bbox.h
@@ -21,7 +21,7 @@
 #include <boost/graph/graph_traits.hpp>
 
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 
 namespace CGAL {
 
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/border.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/border.h
index 362d74025c2..c3a1581c80e 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/border.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/border.h
@@ -19,7 +19,7 @@
 #include <CGAL/boost/graph/iterator.h>
 #include <CGAL/boost/graph/helpers.h>
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 
 #include <boost/graph/graph_traits.hpp>
 
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/compute_normal.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/compute_normal.h
index 2cd837e7bf8..3e10ac976f2 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/compute_normal.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/compute_normal.h
@@ -17,7 +17,7 @@
 #include <CGAL/license/Polygon_mesh_processing/Compute_normal.h>
 
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 
 #include <CGAL/boost/graph/helpers.h>
 #include <CGAL/boost/graph/properties.h>
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/connected_components.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/connected_components.h
index 9a20035268d..d98734581d7 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/connected_components.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/connected_components.h
@@ -42,7 +42,7 @@
 #include <CGAL/tuple.h>
 
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 
 namespace CGAL {
 namespace Polygon_mesh_processing{
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/detect_features.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/detect_features.h
index a2d1b368140..b45fe3989ad 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/detect_features.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/detect_features.h
@@ -18,7 +18,7 @@
 
 #include <CGAL/Kernel/global_functions_3.h>
 #include <CGAL/Polygon_mesh_processing/compute_normal.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 #include <CGAL/boost/graph/properties.h>
 #include <CGAL/Polygon_mesh_processing/connected_components.h>
 
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/distance.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/distance.h
index c4ab5aa0a1b..4237fa85b6f 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/distance.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/distance.h
@@ -26,7 +26,7 @@
 #include <CGAL/AABB_face_graph_triangle_primitive.h>
 #include <CGAL/utility.h>
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 #include <CGAL/point_generators_3.h>
 #include <CGAL/Spatial_sort_traits_adapter_3.h>
 #include <CGAL/spatial_sort.h>
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/fair.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/fair.h
index 528f501d83c..12a09222bdb 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/fair.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/fair.h
@@ -19,7 +19,7 @@
 
 #include <CGAL/Polygon_mesh_processing/internal/fair_impl.h>
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 #include <CGAL/Weights/cotangent_weights.h>
 
 #if defined(CGAL_EIGEN3_ENABLED)
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Smoothing/curvature_flow_impl.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Smoothing/curvature_flow_impl.h
index 66ecda4314e..3757f23f7d6 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Smoothing/curvature_flow_impl.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Smoothing/curvature_flow_impl.h
@@ -18,7 +18,7 @@
 
 #include <CGAL/Polygon_mesh_processing/measure.h>
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 #include <CGAL/Weights/cotangent_weights.h>
 #include <CGAL/Dynamic_property_map.h>
 #include <CGAL/utility.h>
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Snapping/helper.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Snapping/helper.h
index ce67cc83a84..a2087327e98 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Snapping/helper.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Snapping/helper.h
@@ -18,7 +18,7 @@
 #include <CGAL/boost/graph/iterator.h>
 #include <CGAL/number_utils.h>
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 
 namespace CGAL {
 namespace Polygon_mesh_processing {
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Snapping/snap.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Snapping/snap.h
index 4520e825de5..60422c492f0 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Snapping/snap.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Snapping/snap.h
@@ -26,7 +26,7 @@
 #include <CGAL/Polygon_mesh_processing/internal/Snapping/snap_vertices.h>
 
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 #include <CGAL/Polygon_mesh_processing/border.h>
 #include <CGAL/Polygon_mesh_processing/compute_normal.h>
 
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Snapping/snap_vertices.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Snapping/snap_vertices.h
index 91f1a51952b..a31a91b2c96 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Snapping/snap_vertices.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Snapping/snap_vertices.h
@@ -23,7 +23,7 @@
 
 #include <CGAL/Polygon_mesh_processing/internal/Snapping/helper.h>
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 #include <CGAL/Polygon_mesh_processing/border.h>
 
 #include <CGAL/assertions.h>
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/named_params_helper.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/named_params_helper.h
deleted file mode 100644
index 38d431e8005..00000000000
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/named_params_helper.h
+++ /dev/null
@@ -1,19 +0,0 @@
-// Copyright (c) 2015 GeometryFactory (France).
-// All rights reserved.
-//
-// This file is part of CGAL (www.cgal.org).
-//
-// $URL$
-// $Id$
-// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
-//
-// Author(s)     : Jane Tournois
-
-#ifndef CGAL_NAMED_PARAMETERS_HELPERS_H
-#define CGAL_NAMED_PARAMETERS_HELPERS_H
-
-#include <CGAL/license/Polygon_mesh_processing/core.h>
-
-#include <CGAL/boost/graph/named_params_helper.h>
-
-#endif //CGAL_NAMED_PARAMETERS_HELPERS_H
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/intersection.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/intersection.h
index b4c79ee345c..23256eb00b6 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/intersection.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/intersection.h
@@ -23,7 +23,7 @@
 #include <CGAL/boost/iterator/counting_iterator.hpp>
 #include <CGAL/box_intersection_d.h>
 #include <CGAL/Polygon_mesh_processing/internal/Corefinement/intersection_impl.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 #include <CGAL/Polygon_mesh_processing/bbox.h>
 #include <CGAL/Polygon_mesh_processing/connected_components.h>
 #include <CGAL/Side_of_triangle_mesh.h>
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/locate.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/locate.h
index 323c0fbb089..8c9c7042429 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/locate.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/locate.h
@@ -25,7 +25,7 @@
 #include <CGAL/Kernel_traits.h>
 #include <CGAL/Kernel/global_functions.h>
 #include <CGAL/number_utils.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 #include <CGAL/Random.h>
 #include <CGAL/use.h>
 
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/manifoldness.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/manifoldness.h
index 096cbd61ff5..6cf92c50cc7 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/manifoldness.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/manifoldness.h
@@ -16,7 +16,7 @@
 #include <CGAL/license/Polygon_mesh_processing/repair.h>
 
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 
 #include <CGAL/algorithm.h>
 #include <CGAL/assertions.h>
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/measure.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/measure.h
index 85b8dea7f29..3141f2d2128 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/measure.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/measure.h
@@ -22,7 +22,7 @@
 #include <CGAL/boost/graph/helpers.h>
 #include <CGAL/boost/graph/properties.h>
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 
 
 #include <CGAL/Lazy.h> // needed for CGAL::exact(FT)/CGAL::exact(Lazy_exact_nt<T>)
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/merge_border_vertices.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/merge_border_vertices.h
index b0a97548d83..50b87830d8b 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/merge_border_vertices.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/merge_border_vertices.h
@@ -20,7 +20,7 @@
 #include <CGAL/boost/graph/properties.h>
 #include <CGAL/Polygon_mesh_processing/border.h>
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 #include <CGAL/Polygon_mesh_processing/stitch_borders.h>
 
 #include <algorithm>
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/orientation.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/orientation.h
index 31595ae0213..10ab1ec8854 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/orientation.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/orientation.h
@@ -22,7 +22,7 @@
 #include <CGAL/Polygon_mesh_processing/stitch_borders.h>
 #include <CGAL/Polygon_mesh_processing/compute_normal.h>
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 #include <CGAL/Polygon_mesh_processing/self_intersections.h>
 #include <CGAL/Side_of_triangle_mesh.h>
 #include <CGAL/Projection_traits_xy_3.h>
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/random_perturbation.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/random_perturbation.h
index ffde3e90d83..08875a0b9e8 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/random_perturbation.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/random_perturbation.h
@@ -20,7 +20,7 @@
 #include <CGAL/Polygon_mesh_processing/internal/Isotropic_remeshing/remesh_impl.h>
 
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 
 #include <CGAL/AABB_tree.h>
 #include <CGAL/AABB_traits.h>
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/refine.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/refine.h
index 99dfd990136..38fe4ff0608 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/refine.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/refine.h
@@ -17,7 +17,7 @@
 
 
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 
 #include <CGAL/Polygon_mesh_processing/internal/refine_impl.h>
 
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/remesh.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/remesh.h
index 9b6b8c173c9..6b37ec946ea 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/remesh.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/remesh.h
@@ -20,7 +20,7 @@
 #include <CGAL/Polygon_mesh_processing/internal/Isotropic_remeshing/remesh_impl.h>
 
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 
 #ifdef CGAL_PMP_REMESHING_VERBOSE
 #include <CGAL/Timer.h>
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/repair_polygon_soup.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/repair_polygon_soup.h
index 7652a94e42f..23a6ac92904 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/repair_polygon_soup.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/repair_polygon_soup.h
@@ -15,7 +15,7 @@
 #include <CGAL/license/Polygon_mesh_processing/repair.h>
 
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 
 #include <CGAL/Container_helper.h>
 #include <CGAL/iterator.h>
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/self_intersections.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/self_intersections.h
index 30d6190bdc8..cc07ed99f65 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/self_intersections.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/self_intersections.h
@@ -22,7 +22,7 @@
 #include <CGAL/disable_warnings.h>
 
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 
 #include <CGAL/algorithm.h>
 #include <CGAL/Bbox_3.h>
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/shape_predicates.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/shape_predicates.h
index 63813d2186a..c272f9309f2 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/shape_predicates.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/shape_predicates.h
@@ -17,7 +17,7 @@
 #include <CGAL/license/Polygon_mesh_processing/repair.h>
 
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 
 #include <CGAL/array.h>
 #include <CGAL/boost/graph/iterator.h>
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/stitch_borders.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/stitch_borders.h
index abe9160944c..9cb67d0cb4e 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/stitch_borders.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/stitch_borders.h
@@ -20,7 +20,7 @@
 #include <CGAL/boost/graph/properties.h>
 
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 #include <CGAL/Polygon_mesh_processing/border.h>
 #include <CGAL/Polygon_mesh_processing/connected_components.h>
 #include <CGAL/Polygon_mesh_processing/shape_predicates.h>
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/transform.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/transform.h
index 606db68b196..9f4cfd5a691 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/transform.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/transform.h
@@ -14,7 +14,7 @@
 #include <CGAL/license/Polygon_mesh_processing/core.h>
 
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 
 namespace CGAL{
 namespace Polygon_mesh_processing{
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/triangle.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/triangle.h
index 7a131523f37..78152388107 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/triangle.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/triangle.h
@@ -19,7 +19,7 @@
 #include <boost/graph/graph_traits.hpp>
 
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 
 namespace CGAL {
 
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/triangulate_faces.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/triangulate_faces.h
index 0b48967f273..8b8cec2e239 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/triangulate_faces.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/triangulate_faces.h
@@ -32,7 +32,7 @@
 #include <CGAL/Polygon_mesh_processing/triangulate_hole.h>
 #include <CGAL/Polygon_mesh_processing/compute_normal.h>
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 
 #include <boost/range/size.hpp>
 
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/triangulate_hole.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/triangulate_hole.h
index 71351e37125..55dcacfff7f 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/triangulate_hole.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/triangulate_hole.h
@@ -23,7 +23,7 @@
 #include <CGAL/Polygon_mesh_processing/fair.h>
 
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 
 #include <CGAL/boost/graph/helpers.h>
 
diff --git a/Polyhedron/demo/Polyhedron/Plugins/IO/VTK_io_plugin.cpp b/Polyhedron/demo/Polyhedron/Plugins/IO/VTK_io_plugin.cpp
index 28a0be5359e..999a81bc2cf 100644
--- a/Polyhedron/demo/Polyhedron/Plugins/IO/VTK_io_plugin.cpp
+++ b/Polyhedron/demo/Polyhedron/Plugins/IO/VTK_io_plugin.cpp
@@ -68,7 +68,7 @@
 #include <vtkXMLUnstructuredGridWriter.h>
 
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 typedef Scene_surface_mesh_item Scene_facegraph_item;
 typedef Scene_facegraph_item::Face_graph FaceGraph;
 typedef boost::property_traits<boost::property_map<FaceGraph,
diff --git a/Polyhedron/demo/Polyhedron/include/CGAL/IO/read_surf_trianglemesh.h b/Polyhedron/demo/Polyhedron/include/CGAL/IO/read_surf_trianglemesh.h
index f2bd4e37871..99f8ea9bac3 100644
--- a/Polyhedron/demo/Polyhedron/include/CGAL/IO/read_surf_trianglemesh.h
+++ b/Polyhedron/demo/Polyhedron/include/CGAL/IO/read_surf_trianglemesh.h
@@ -9,7 +9,7 @@
 #include <CGAL/Polygon_mesh_processing/repair.h>
 
 #include <CGAL/Named_function_parameters.h>
-#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
+#include <CGAL/boost/graph/named_params_helper.h>
 
 //a material is composed of an material Id and a material name.
 typedef std::pair<int, std::string> material;
diff --git a/STL_Extension/include/CGAL/assertions_behaviour.h b/STL_Extension/include/CGAL/assertions_behaviour.h
index a8bcb45fcf8..e70cf1e1169 100644
--- a/STL_Extension/include/CGAL/assertions_behaviour.h
+++ b/STL_Extension/include/CGAL/assertions_behaviour.h
@@ -14,11 +14,11 @@
 //
 // Author(s)     : Geert-Jan Giezeman and Sven Schoenherr
 
-#include <CGAL/config.h>
-
 #ifndef CGAL_ASSERTIONS_BEHAVIOUR_H
 #define CGAL_ASSERTIONS_BEHAVIOUR_H
 
+#include <CGAL/config.h>
+
 // workaround against the definition of EXIT in <opencv2/core/internal.hpp>
 #ifdef EXIT
 #  undef EXIT