diff --git a/src/python/WMCore/Services/DBS/DBS3Reader.py b/src/python/WMCore/Services/DBS/DBS3Reader.py
index ca55f44e3f9..ea792611b97 100644
--- a/src/python/WMCore/Services/DBS/DBS3Reader.py
+++ b/src/python/WMCore/Services/DBS/DBS3Reader.py
@@ -21,6 +21,7 @@
 from retry import retry
 
 from Utils.IteratorTools import grouper
+from Utils.PythonVersion import PY2
 from WMCore.Services.DBS.DBSErrors import DBSReaderError, formatEx3
 
 
@@ -42,7 +43,7 @@ def remapDBS3Keys(data, stringify=False, **others):
                'block_name': 'BlockName', 'lumi_section_num': 'LumiSectionNumber'}
 
     mapping.update(others)
-    formatFunc = lambda x: encodeUnicodeToBytes(x) if stringify else x
+    formatFunc = lambda x: encodeUnicodeToBytes(x) if PY2 and stringify else x
     for name, newname in viewitems(mapping):
         if name in data:
             data[newname] = formatFunc(data[name])