diff --git a/update_db.py b/update_db.py
index 3d551a0..439d3f3 100644
--- a/update_db.py
+++ b/update_db.py
@@ -9,6 +9,7 @@ import os
 import random
 import string
 import time
+import unicodedata
 from dataclasses import dataclass
 from datetime import date, datetime, timedelta
 from typing import Any, Type, TypedDict, cast
@@ -158,7 +159,7 @@ def update_tables (
             for vt in video_tags:
                 tag = tag_dao.find (vt.tag_id)
                 if (tag is not None
-                        and (tag.name.upper () not in map (str.upper, tag_names))
+                        and (normalise (tag.name) not in map (normalise, tag_names))
                         and (tag.id_ is not None)):
                     tag_ids.append (tag.id_)
             video_tag_dao.untag_all (video.id_, tag_ids, now)
@@ -1067,5 +1068,11 @@ class UserDto:
     id_:    int | None  = None
 
 
+def normalise (
+        s:  str
+) -> str:
+    return unicodedata.normalize ('NFKC', s).lower ()
+
+
 if __name__ == '__main__':
     main ()