1) drop and recreate SP => dont' work

2) clear all cache for this SP => don't work

3) restart SQL => don't work

4) created a new SP with a different name but the same code => it's work

a strange thing :

the SQL login is in french, with this login in SSMS, it's ok

the connexion string in application have "current language=french"=> not ok

set the connexion string in application to "current language=english"=> ok (but I can't change the connexion string definitely)

change SQL login to english and connexion string "current language=french" => not ok

I don't understand