Thank you for you help.
I tried your tips but the problem remains. Example:
$ echo "SendEnv LANG LC_ALL" > ~/.ssh/config $ LANG=C; export LANG; LC_ALL=C; export LC_ALL $ ssh aa@quercy You are required to change your password immediately (root enforced) Last login: Fri Oct 30 15:02:34 2015 from quercy WARNING: Your password has expired. You must change your password now and login again! Changement de mot de passe pour l'utilisateur aa. Nouveau mot de passe : MOT DE PASSE INCORRECT : BEAUCOUP trop court