diff --git a/watchlist/models.py b/watchlist/models.py
index 0bc86fd..5a984c6 100644
--- a/watchlist/models.py
+++ b/watchlist/models.py
@@ -6,7 +6,7 @@ from django.contrib.auth.models import User
 from django.contrib import admin
 
 IMDB_ID_RE = re.compile(r'(?P<id>tt\d{7,})')
-CSFD_ID_RE = re.compile(r'(?P<id>\d+)')
+CSFD_ID_RE = re.compile(r'(?P<id>[1-9]\d*)')
 
 def validate_imdb_id(v: str) -> bool:
     return IMDB_ID_RE.match(v)