About languages : site language vs admin language

Hi there !

Well after many test we decided for our multilingual sites to... make separates sites.

But now appear a problem. If I want the frontend to be en english (specially for the theme) BUT I want the admin in french, well dont find out our to do that. If I choose english in settings/site language, the front end is good in english but also the backend !

Did not thought about that issu, is there any way to separate the front end language from the backend ?

Thanks