diff --git a/app.py b/app.py
index 7295042..12662ed 100644
--- a/app.py
+++ b/app.py
@@ -22,7 +22,8 @@ app.logger.setLevel(logging.INFO)
 
 @app.before_request
 def _set_language():
-    lang = request.cookies.get("lang", "de")
+    # URL parameter ?lang= takes priority over cookie
+    lang = request.args.get("lang") or request.cookies.get("lang", "de")
     if lang not in TRANSLATIONS:
         lang = "de"
     g.lang = lang