diff --git a/dune/gfe/parallel/globalp2mapper.hh b/dune/gfe/parallel/globalp2mapper.hh
index 55c988059ca2aa5495cf0c09bebdae07be36d339..1bb6a3ede3732e9e59d3c1e50b1cc0b586ebe1f1 100644
--- a/dune/gfe/parallel/globalp2mapper.hh
+++ b/dune/gfe/parallel/globalp2mapper.hh
@@ -33,6 +33,9 @@ namespace Dune {
     {
       static_assert(GridView::dimension==2, "Only implemented for two-dimensional grids");
 
+      if (gridView.size(GeometryTypes::triangle)>1)
+        DUNE_THROW(NotImplemented, "GlobalP2Mapper only works for quad grids!");
+
       GlobalIndexSet<GridView> globalVertexIndex(gridView,2);
       GlobalIndexSet<GridView> globalEdgeIndex(gridView,1);
       GlobalIndexSet<GridView> globalElementIndex(gridView,0);