diff --git a/Shape_detection/include/CGAL/Shape_detection/Efficient_RANSAC/Octree.h b/Shape_detection/include/CGAL/Shape_detection/Efficient_RANSAC/Octree.h
index 9e6aca8c3d6..66b3df09f9a 100644
--- a/Shape_detection/include/CGAL/Shape_detection/Efficient_RANSAC/Octree.h
+++ b/Shape_detection/include/CGAL/Shape_detection/Efficient_RANSAC/Octree.h
@@ -89,7 +89,7 @@ public:
   }
 
   std::size_t maxLevel() const {
-    return m_octree.max_depth_reached();
+    return m_octree.max_depth_reached() - 1;
   }
 
   std::size_t offset() const { return m_offset; }