diff --git a/pdeutils/fespaces/lagrangeBasis.m b/pdeutils/fespaces/lagrangeBasis.m
index ffbfe05bd262d38aa9707e515ba10755e7e2a497..3f66a8e625036b25b5243e9a9af8f63364e992ca 100644
--- a/pdeutils/fespaces/lagrangeBasis.m
+++ b/pdeutils/fespaces/lagrangeBasis.m
@@ -20,6 +20,9 @@ function B = lagrangeBasis(dim, order)
             'order', @(grid, elementIndex)(1),...
             'index', @P1Index,...
             'size', @(grid)(size(grid.nodes,2)));
+    else
+        error( 'The chosen parameters (dim=%d, order=%d) are not supported.', ...
+                dim, order );
     end
 
 end