diff --git a/Periodic_3_mesh_3/test/Periodic_3_mesh_3/test_implicit_shapes_bunch.cpp b/Periodic_3_mesh_3/test/Periodic_3_mesh_3/test_implicit_shapes_bunch.cpp
index b39838e6dc7..f09fffd0d4f 100644
--- a/Periodic_3_mesh_3/test/Periodic_3_mesh_3/test_implicit_shapes_bunch.cpp
+++ b/Periodic_3_mesh_3/test/Periodic_3_mesh_3/test_implicit_shapes_bunch.cpp
@@ -202,7 +202,7 @@ int main()
   Iso_cuboid canonical_cube(0, 0, 0, domain_size, domain_size, domain_size);
 
   // Array of the functions
-  const int functions_count = 11;
+  const unsigned int functions_count = 11;
 
   std::array<Periodic_function, functions_count> implicit_functions =
   {{
@@ -219,7 +219,7 @@ int main()
     Periodic_function(split_p, canonical_cube)
   }};
 
-  for(int i=0; i<functions_count; ++i)
+  for(unsigned int i=0; i<functions_count; ++i)
   {
     // Periodic mesh domain
     Periodic_mesh_domain domain =
diff --git a/Periodic_3_triangulation_3/include/CGAL/Periodic_3_triangulation_3/internal/Periodic_3_triangulation_dummy_generator.h b/Periodic_3_triangulation_3/include/CGAL/Periodic_3_triangulation_3/internal/Periodic_3_triangulation_dummy_generator.h
index ef1179b8630..1070d174871 100644
--- a/Periodic_3_triangulation_3/include/CGAL/Periodic_3_triangulation_3/internal/Periodic_3_triangulation_dummy_generator.h
+++ b/Periodic_3_triangulation_3/include/CGAL/Periodic_3_triangulation_3/internal/Periodic_3_triangulation_dummy_generator.h
@@ -38,9 +38,9 @@ insert_generic_dummy_points()
             << domain().zmin() << " " << domain().zmax() << std::endl;
 #endif
 
-  int min_pos = std::min_element(std::cbegin(spans), std::cend(spans)) - std::cbegin(spans);
-  int max_pos = std::max_element(std::cbegin(spans), std::cend(spans)) - std::cbegin(spans);
-  int mid_pos;
+  std::size_t min_pos = std::min_element(std::cbegin(spans), std::cend(spans)) - std::cbegin(spans);
+  std::size_t max_pos = std::max_element(std::cbegin(spans), std::cend(spans)) - std::cbegin(spans);
+  std::size_t mid_pos;
 
   if(min_pos == max_pos) // cubic
   {