diff --git a/DDSim/DD4hepSimulation.py b/DDSim/DD4hepSimulation.py
index d4a79192fe89d2fedd36c7d39e1a1cd2844c0cbe..52a2b4667abcc589a93120f77c5d68db6f9d6ef4 100644
--- a/DDSim/DD4hepSimulation.py
+++ b/DDSim/DD4hepSimulation.py
@@ -279,12 +279,12 @@ class DD4hepSimulation(object):
     import ROOT
     ROOT.PyConfig.IgnoreCommandLineOptions = True
 
-    import DDG4, DD4hep
+    import DDG4, dd4hep
 
     self.printLevel = getOutputLevel(self.printLevel)
 
     kernel = DDG4.Kernel()
-    DD4hep.setPrintLevel(self.printLevel)
+    dd4hep.setPrintLevel(self.printLevel)
     #kernel.setOutputLevel('Compact',1)
 
     kernel.loadGeometry("file:"+ self.compactFile )
@@ -479,7 +479,7 @@ class DD4hepSimulation(object):
     ph.addPhysicsConstructor('G4StepLimiterPhysics')
     _phys.add(ph)
 
-    DD4hep.setPrintLevel(self.printLevel)
+    dd4hep.setPrintLevel(self.printLevel)
 
     kernel.configure()
     kernel.initialize()