diff --git a/src/qkit/storage/hdf_DateTimeGenerator.py b/src/qkit/storage/hdf_DateTimeGenerator.py
index 34f14ec1..10053936 100644
--- a/src/qkit/storage/hdf_DateTimeGenerator.py
+++ b/src/qkit/storage/hdf_DateTimeGenerator.py
@@ -64,12 +64,19 @@ def new_filename_v2(self, name):
             filename += '_' + str(name)
         self.returndict['_filename'] = filename + '.h5'
         '''New filename with datadir/run_id/user/uuid_name/uuid_name.h5'''
+
+        path_components = [
+            qkit.cfg.get('run_id', 'NO_RUN').strip().replace(" ", "_").upper(),
+            qkit.cfg.get('user', 'John_Doe').strip().replace(" ", "_")
+        ]
+
+        path_extension = qkit.cfg.get('path_extension')
+        if path_extension is not None and path_extension:
+            path_components.append(str(path_extension))
         
-        self.returndict['_relfolder'] = os.path.join(
-                qkit.cfg.get('run_id', 'NO_RUN').strip().replace(" ", "_").upper(),
-                qkit.cfg.get('user', 'John_Doe').strip().replace(" ", "_"),
-                filename
-        )
+        path_components.append(filename)
+        
+        self.returndict['_relfolder'] = os.path.join(*path_components)
 
 
 def encode_uuid(value):
diff --git a/tests/DTG_test.py b/tests/DTG_test.py
new file mode 100644
index 00000000..bb3e7af9
--- /dev/null
+++ b/tests/DTG_test.py
@@ -0,0 +1,15 @@
+import pytest
+from qkit.storage.hdf_DateTimeGenerator import DateTimeGenerator
+import qkit
+import re
+
+def test_DateTimeGenerator_no_extension():
+    dtg = DateTimeGenerator()
+    returndict = dtg.new_filename("test_file.h5")
+    assert re.match("NO_RUN/John_Doe/......_test_file\\.h5", returndict['_relfolder']) 
+
+def test_DateTimeGenerator_with_extension():
+    qkit.cfg['path_extension'] = 'extension'
+    dtg = DateTimeGenerator()
+    returndict = dtg.new_filename("test_file.h5")
+    assert re.match("NO_RUN/John_Doe/extension/......_test_file\\.h5", returndict['_relfolder']) 
\ No newline at end of file