diff --git a/mo/web/org_place.py b/mo/web/org_place.py
index e63cf5966c951aa9694cdcd6295386a028f44636..a04ca1885318c67824bc10a462612a42ff34e12c 100644
--- a/mo/web/org_place.py
+++ b/mo/web/org_place.py
@@ -71,6 +71,10 @@ class PlaceEditForm(FlaskForm):
     )
     submit = wtforms.SubmitField('Uložit')
 
+    def validate_code(form: FlaskForm, field: mo_fields.String) -> None:
+        if field.data is not None and field.data.startswith('#'):
+            raise wtforms.ValidationError('Kód nesmí začínat na znak "#".')
+
 
 class PlaceSchoolEditForm(PlaceEditForm):
     red_izo = mo_fields.String('RED_IZO')