diff --git a/src/Mod/Part/App/GeometryCurvePyImp.cpp b/src/Mod/Part/App/GeometryCurvePyImp.cpp
index 1c8966e77..03bf44e8e 100644
--- a/src/Mod/Part/App/GeometryCurvePyImp.cpp
+++ b/src/Mod/Part/App/GeometryCurvePyImp.cpp
@@ -45,6 +45,7 @@
 # include <GeomAPI_ProjectPointOnCurve.hxx>
 # include <GeomConvert_ApproxCurve.hxx>
 # include <Standard_Failure.hxx>
+# include <Standard_NullValue.hxx>
 # include <ShapeConstruct_Curve.hxx>
 #endif
 
@@ -356,6 +357,8 @@ PyObject* GeometryCurvePy::toBSpline(PyObject * args)
                 return 0;
             ShapeConstruct_Curve scc;
             Handle_Geom_BSplineCurve spline = scc.ConvertToBSpline(c, u, v, Precision::Confusion());
+            if (spline.IsNull())
+                Standard_NullValue::Raise("Conversion to B-Spline failed");
             return new BSplineCurvePy(new GeomBSplineCurve(spline));
         }
     }