Lorsque l'on a ce message là:

perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
    LANGUAGE = (unset),
    LC_ALL = (unset),
    LANG = "fr_FR.UTF-8"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").

Solution :

sudo locale-gen fr_FR.UTF-8

Sinon, essayer aussi:

sudo dpkg-reconfigure locales

Pour voir ce qui est paramétré actuellement:

printenv |   egrep '(LC_*|LANG)'