diff --git a/nifty6/operators/operator.py b/nifty6/operators/operator.py
index b33df6973fab3ba6a3efbcdcf28721c06ca384d7..e38faefc9e38f97455c52fd58f1a41455894ffe0 100644
--- a/nifty6/operators/operator.py
+++ b/nifty6/operators/operator.py
@@ -294,10 +294,11 @@ class Operator(metaclass=NiftyMeta):
 
     def _simplify_for_constant_input_nontrivial(self, c_inp):
         from .simplify_for_const import SlowPartialConstantOperator
-        s = ('SlowPartialConstantOperator used. You might want to consider',
-             ' implementing `_simplify_for_constant_input_nontrivial()` for',
-             ' this operator.')
+        s = ('SlowPartialConstantOperator used. You might want to consider'
+             ' implementing `_simplify_for_constant_input_nontrivial()` for'
+             ' this operator:')
         logger.warning(s)
+        logger.warning(self.__repr__())
         return None, self @ SlowPartialConstantOperator(self.domain, c_inp.keys())
 
     def ptw(self, op, *args, **kwargs):