diff --git a/Combinatorial_map/include/CGAL/Combinatorial_map.h b/Combinatorial_map/include/CGAL/Combinatorial_map.h
index 7fb9471cf6b..01133a51bb8 100644
--- a/Combinatorial_map/include/CGAL/Combinatorial_map.h
+++ b/Combinatorial_map/include/CGAL/Combinatorial_map.h
@@ -743,6 +743,8 @@ namespace CGAL {
     bool is_reserved(int amark) const
     {
       CGAL_assertion(amark>=0 && (size_type)amark<NB_MARKS);
+      CGAL_assume( (size_type)amark<NB_MARKS );
+
       return (mnb_times_reserved_marks[(size_type)amark]!=0);
     }
 
@@ -753,6 +755,8 @@ namespace CGAL {
     size_type number_of_marked_darts(int amark) const
     {
       CGAL_assertion( is_reserved(amark) );
+      CGAL_assume( (size_type)amark<NB_MARKS );
+
       return mnb_marked_darts[(size_type)amark];
     }
 
@@ -813,14 +817,21 @@ namespace CGAL {
     void share_a_mark(int amark) const
     {
       CGAL_assertion( is_reserved(amark) );
-      ++mnb_times_reserved_marks[amark];
+      CGAL_assume( (size_type)amark<NB_MARKS );
+
+      ++mnb_times_reserved_marks[(size_type)amark];
     }
 
     /** @return the number of times a mark is reserved.
      *  @param amark the mark to share.
      */
     size_type get_number_of_times_mark_reserved(int amark) const
-    { return mnb_times_reserved_marks[amark]; }
+    {
+      CGAL_assertion( (size_type)amark<NB_MARKS );
+      CGAL_assume( (size_type)amark<NB_MARKS );
+
+      return mnb_times_reserved_marks[amark];
+    }
 
     /** Negate the mark of all the darts for a given mark.
      * After this call, all the marked darts become unmarked and all the
@@ -830,6 +841,7 @@ namespace CGAL {
     void negate_mark(int amark) const
     {
       CGAL_assertion( is_reserved(amark) );
+      CGAL_assume( (size_type)amark<NB_MARKS );
 
       mnb_marked_darts[amark] = number_of_darts() - mnb_marked_darts[amark];
 
@@ -845,6 +857,7 @@ namespace CGAL {
     {
       // CGAL_assertion( adart != null_dart_handle );
       CGAL_assertion( is_reserved(amark) );
+      CGAL_assume( (size_type)amark<NB_MARKS );
 
       return get_dart_mark(adart, amark)!=mmask_marks[(size_type)amark];
     }
@@ -859,6 +872,7 @@ namespace CGAL {
     {
       CGAL_assertion( adart != null_dart_handle );
       CGAL_assertion( is_reserved(amark) );
+      CGAL_assume( (size_type)amark<NB_MARKS );
 
       if (is_marked(adart, amark) != astate)
       {
@@ -877,6 +891,7 @@ namespace CGAL {
     {
       CGAL_assertion( adart != null_dart_handle );
       CGAL_assertion( is_reserved(amark) );
+      CGAL_assume( (size_type)amark<NB_MARKS );
 
       if (is_marked(adart, amark)) return;
 
@@ -892,6 +907,7 @@ namespace CGAL {
     {
       CGAL_assertion( adart != null_dart_handle );
       CGAL_assertion( is_reserved(amark) );
+      CGAL_assume( (size_type)amark<NB_MARKS );
 
       if (!is_marked(adart, amark)) return;
 
@@ -907,6 +923,7 @@ namespace CGAL {
     void mark_null_dart(int amark) const
     {
       CGAL_assertion( is_reserved(amark) );
+      CGAL_assume( (size_type)amark<NB_MARKS );
 
 #ifdef CGAL_CMAP_DEPRECATED
       if ( null_dart_handle!=NULL ) // Pb with static null_dart_handle for windows
@@ -920,6 +937,7 @@ namespace CGAL {
     void unmark_null_dart(int amark) const
     {
       CGAL_assertion( is_reserved(amark) );
+      CGAL_assume( (size_type)amark<NB_MARKS );
 
 #ifdef CGAL_CMAP_DEPRECATED
       if ( null_dart_handle!=NULL ) // Pb with static null_dart_handle for windows
@@ -956,6 +974,7 @@ namespace CGAL {
     void free_mark(int amark) const
     {
       CGAL_assertion( is_reserved(amark) );
+      CGAL_assume( (size_type)amark<NB_MARKS );
 
       if ( mnb_times_reserved_marks[amark]>1 )
       {