diff --git a/Kernel_23/examples/Kernel_23/MyKernel.C b/Kernel_23/examples/Kernel_23/MyKernel.cpp
similarity index 100%
rename from Kernel_23/examples/Kernel_23/MyKernel.C
rename to Kernel_23/examples/Kernel_23/MyKernel.cpp
diff --git a/Kernel_23/examples/Kernel_23/makefile b/Kernel_23/examples/Kernel_23/makefile
index 4c675222461..687b8280634 100644
--- a/Kernel_23/examples/Kernel_23/makefile
+++ b/Kernel_23/examples/Kernel_23/makefile
@@ -51,7 +51,7 @@ test_polyhedron_prog_incr_builder.clean
 #                    suffix rules
 #---------------------------------------------------------------------#
 
-.C$(OBJ_EXT):
+.cpp$(OBJ_EXT):
 	$(CGAL_CXX) $(CXXFLAGS) $(OBJ_OPT) $<
 
 .cpp$(OBJ_EXT):
diff --git a/Kernel_23/examples/Kernel_23/test_delaunay_2.C b/Kernel_23/examples/Kernel_23/test_delaunay_2.cpp
similarity index 100%
rename from Kernel_23/examples/Kernel_23/test_delaunay_2.C
rename to Kernel_23/examples/Kernel_23/test_delaunay_2.cpp
diff --git a/Kernel_23/examples/Kernel_23/test_polyhedron_prog_incr_builder.C b/Kernel_23/examples/Kernel_23/test_polyhedron_prog_incr_builder.cpp
similarity index 100%
rename from Kernel_23/examples/Kernel_23/test_polyhedron_prog_incr_builder.C
rename to Kernel_23/examples/Kernel_23/test_polyhedron_prog_incr_builder.cpp
diff --git a/Kernel_23/examples/Kernel_23/test_polyhedron_prog_incr_builder_own_archetype.C b/Kernel_23/examples/Kernel_23/test_polyhedron_prog_incr_builder_own_archetype.cpp
similarity index 100%
rename from Kernel_23/examples/Kernel_23/test_polyhedron_prog_incr_builder_own_archetype.C
rename to Kernel_23/examples/Kernel_23/test_polyhedron_prog_incr_builder_own_archetype.cpp