diff --git a/app/routes/users.py b/app/routes/users.py
index 0634109..fe16432 100644
--- a/app/routes/users.py
+++ b/app/routes/users.py
@@ -404,7 +404,7 @@ def settings_form(username):
     else:
         rendered_sig = ''
     session['subscribe_by_default'] = request.form.get('subscribe_by_default', default='off') == 'on'
-    display_name = request.form.get('display_name', default='')
+    display_name = request.form.get('display_name', default='').replace('@', '_')
     if not validate_display_name(display_name):
         flash('Invalid display name.', InfoboxKind.ERROR)
         return redirect('.settings', username=user.username)