diff --git a/Polyhedron/demo/Polyhedron/Polyhedron_demo_repair_polyhedron_plugin.cpp b/Polyhedron/demo/Polyhedron/Polyhedron_demo_repair_polyhedron_plugin.cpp
index 7d6579342e1..00b9729d154 100644
--- a/Polyhedron/demo/Polyhedron/Polyhedron_demo_repair_polyhedron_plugin.cpp
+++ b/Polyhedron/demo/Polyhedron/Polyhedron_demo_repair_polyhedron_plugin.cpp
@@ -1,10 +1,10 @@
 #include <QtCore/qglobal.h>
 
 #include "Scene_polyhedron_item.h"
-#include "Scene_interface.h"
+#include <CGAL/Three/Scene_interface.h>
 #include "Polyhedron_type.h"
-#include "Polyhedron_demo_plugin_interface.h"
-#include "Polyhedron_demo_plugin_helper.h"
+#include <CGAL/Three/Polyhedron_demo_plugin_interface.h>
+#include <CGAL/Three/Polyhedron_demo_plugin_helper.h>
 #include "Messages_interface.h"
 #include <CGAL/gl.h>
 
@@ -15,12 +15,13 @@
 #include <CGAL/Polygon_mesh_processing/repair.h>
 #include <CGAL/boost/graph/graph_traits_Polyhedron_3.h>
 
+using namespace CGAL::Three;
 class Polyhedron_demo_repair_polyhedron_plugin :
         public QObject,
         public Polyhedron_demo_plugin_helper
 {
     Q_OBJECT
-    Q_INTERFACES(Polyhedron_demo_plugin_interface)
+    Q_INTERFACES(CGAL::Three::Polyhedron_demo_plugin_interface)
     Q_PLUGIN_METADATA(IID "com.geometryfactory.PolyhedronDemo.PluginInterface/1.0")
 
 public: