How to get a resident permit?

A friend of mine is looking forward to stay and study Arabic in Tunis for about a year and maybe to find a job to help with his expenses and interact with locals during his staying.

Any clues about how he can get his resident permit? Do you know if he will be able to legally work with a student permit?

Since for the resident permit a rental contract is required; that could be a problem.

I do have a rental contract on my name for my resident permit but he doesn't. Do you know if I could present a note telling that we will share the house?

Thanks again!
Ivan