diff --git a/dune/matrix-vector/singlenonzerocolumnmatrix.hh b/dune/matrix-vector/singlenonzerocolumnmatrix.hh
index a2c1c15df8305ed5620d388e56df0814edb1177a..7e3ffc366cc7e6ccc420fd59bcef21922bfeb3ed 100644
--- a/dune/matrix-vector/singlenonzerocolumnmatrix.hh
+++ b/dune/matrix-vector/singlenonzerocolumnmatrix.hh
@@ -96,7 +96,7 @@ public:
 
     const_row_reference operator[] (size_type rowIndex) const
     {
-        return const_row_reference(&(static_cast<K&>(nonZeroColumn_[rowIndex])), columnIndex_);
+        return const_row_reference(&(static_cast<const K&>(nonZeroColumn_[rowIndex])), columnIndex_);
     }
 
     size_type nonZeroColumnIndex() const