diff --git a/DDCore/python/dd4hep_base.py b/DDCore/python/dd4hep_base.py
index 3d5073c8d2d4a78540a690133c175ba3fae71733..a62f0542cc4144dd6428d32979f4ed3153feb6c4 100644
--- a/DDCore/python/dd4hep_base.py
+++ b/DDCore/python/dd4hep_base.py
@@ -118,6 +118,8 @@ def unicode_2_string(value):
     value = value
   elif isinstance(value, six.string_types):
     value = str(value)
+  elif isinstance(value, bytes):
+    value = value.decode()
   elif isinstance(value, (list, set, tuple)):
     value = [unicode_2_string(x) for x in value]
   elif isinstance(value, dict):