Set other language than English dont work properly

Hello folks,
I’m trying to prove to my community that Grav can be a better choice for small and funy blog but i guess a lot of issues to setup 100% the language FR for the whole site + admin plugin. I need help to fix it.

Simply, i have set in:

"default_lang: fr"


  supported: fr
  default_lang: fr"

and do the same in the main /config/ folder.

When check out the generated html of the site, i have
When check out the generated html of the adminDashboard, it still on
The Menu in the adminDashboard are 80% english (Ok).
The thing i need it to have the Sidebar content into FRENCH.

The ultimate solution i found is to overwrite the “en” parameters in /user/themes/quark/languages.yaml with French translation. Sincerely, i don’t like this method, which i found dirty.

PS: It is based on Quark squeleton.

Thanks by advance