You can copy and edit the english language
from:
/language/en-GB/en-GB.com_jsn.ini (frontend)
/administrator/language/en-GB/en-GB.com_jsn.ini (backend)
/administrator/language/en-GB/en-GB.com_jsn.sys.ini (backend)
to:
/language/fr-FR/fr-FR.com_jsn.ini (frontend)
/administrator/language/fr-FR/fr-FR.com_jsn.ini (backend)
/administrator/language/fr-FR/fr-FR.com_jsn.sys.ini (backend)
We would be happy if I wanted to share them on our forum