diff --git a/Constrained_triangulation_3/include/CGAL/Conforming_constrained_Delaunay_triangulation_3.h b/Constrained_triangulation_3/include/CGAL/Conforming_constrained_Delaunay_triangulation_3.h
index 0a263211c8c..a4ac3710537 100644
--- a/Constrained_triangulation_3/include/CGAL/Conforming_constrained_Delaunay_triangulation_3.h
+++ b/Constrained_triangulation_3/include/CGAL/Conforming_constrained_Delaunay_triangulation_3.h
@@ -3942,7 +3942,7 @@ protected:
     face_constraint_misses_subfaces[pos] = false;
   }
   static inline constexpr std::size_t face_constraint_misses_subfaces_npos = boost::dynamic_bitset<>::npos;
-  std::vector<CDT_3_signed_index> faces_region_numbers;
+  std::vector<int> faces_region_numbers;
 };
 
 #endif // DOXYGEN_RUNNING