diff --git a/cscripts/csresspec.py b/cscripts/csresspec.py
index 67ae830..ad3f6b7 100755
--- a/cscripts/csresspec.py
+++ b/cscripts/csresspec.py
@@ -539,7 +539,7 @@ class csresspec(ctools.csobservation):
                 # Calculate Model and residuals. If model cube is provided load
                 # it
                 if self._use_maps:
-                    modcube = gammalib.GCTAEventCube(self['inmodel'].filename())
+                    modcube = gammalib.GCTAEventCube(self['modcube'].filename())
 
                 # ... otherwise calculate it now
                 else: