diff --git a/update_db.py b/update_db.py
index d48af1d..fd4bdb1 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
@@ -60,7 +61,7 @@ def update_tables (
         for video_tag in video_tags:
             tag = video_tag.tag
             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))):
                 video_tag.untagged_at = now
                 video_tag.save ()
         for tag_name in tag_names:
@@ -402,5 +403,11 @@ class VideoTagRow (TypedDict):
     untagged_at:    date | None
 
 
+def normalise (
+        s:  str
+) -> str:
+    return unicodedata.normalize ('NFKC', s).lower ()
+
+
 if __name__ == '__main__':
     main ()