diff --git a/cof/settings/common.py b/cof/settings/common.py
index ebc7fb2a..4c853a16 100644
--- a/cof/settings/common.py
+++ b/cof/settings/common.py
@@ -186,7 +186,7 @@ LOGIN_URL = "cof-login"
 LOGIN_REDIRECT_URL = "home"
 
 CAS_SERVER_URL = "https://cas.eleves.ens.fr/"
-CAS_VERSION = "3"
+CAS_VERSION = "2"
 CAS_LOGIN_MSG = None
 CAS_IGNORE_REFERER = True
 CAS_REDIRECT_URL = "/"