diff --git a/Triangulation_3/include/CGAL/Constrained_Delaunay_triangulation_3.h b/Triangulation_3/include/CGAL/Constrained_Delaunay_triangulation_3.h
index 95b84e653ac..4a4533d3845 100644
--- a/Triangulation_3/include/CGAL/Constrained_Delaunay_triangulation_3.h
+++ b/Triangulation_3/include/CGAL/Constrained_Delaunay_triangulation_3.h
@@ -638,7 +638,7 @@ private:
   // Given a region and a border edge of it, returns an edge in the link of the
   // border edge that intersects the region.
   // The returned edge has its first vertex above the region.
-  std::optional<Edge> search_first_intersection(CDT_3_face_index face_index,
+  std::optional<Edge> search_first_intersection(CDT_3_face_index /*face_index*/,
                                                 const CDT_2& cdt_2,
                                                 const auto& fh_region,
                                                 const Edge border_edge)