Front-end (User Interface) default language

Hi,

We have add one more language (French), we need to make French as default language for Front-end (User Interface) and keep English as default for Back-end (Admin panel), But we can't find how to do that !!! when we select FR as Default language in Basic settings or in Languages section, the Admin panel and the Front-end are in Frensh.

Thank you

I found the solution, it's simple (my mistake).
So after we setup FR as a default language, I need just to log out then log in by selecting English from dropdown in the login form.