diff --git a/dune/gfe/cosseratenergystiffness.hh b/dune/gfe/cosseratenergystiffness.hh
index 9aea2674882b66f8cf7ceb08d583eb6253030942..4d1b8060775f947938f59270dfa156bbbec56947 100644
--- a/dune/gfe/cosseratenergystiffness.hh
+++ b/dune/gfe/cosseratenergystiffness.hh
@@ -800,7 +800,7 @@ bendingEnergyGradient(typename TargetSpace::EmbeddedTangentVector& embeddedLocal
                 RT_DR3[i][j] += R[k][i] * DR[k][2][j];
 
     for (int i=0; i<gridDim; i++)
-        assert(std::fabs(RT_DR3[2][i]) < 1e-7);
+        assert(std::abs(RT_DR3[2][i]) < 1e-7);
 
     // -----------------------------------------------------------------------------