Hello!
I think you have to (or rather you'd better to) translate it via Launchpad
as the project is hosted there (including translations). Here is the link to
the translations: https://translations.launchpad.net/ubuntu/+source/ubiquity.
And thanks in advance for translating it into french! ;)
PS: You can choose the version at the bottom of the page (Trisquel 7 is based
on Ubuntu 14.04 and Trisquel 6 on Ubuntu 12.04).
PS 2: I see that the translation is complete for Ubuntu 12.04 and 14.04. If
you still have untranslated strings, it might be because of strings that have
not been configured as to be translated. If this is the case, you should
probably report a bug about this.
