Foyer de jeunes travailleurs is a kind of appartment only for the young single workers. The advantage is not very expensive. It is an ideal place to live temporarily.
For the rent fee, I have no ideas how much it costs but I can tell you that if you want to rent an appt in Clermont, it will cost a little bit 300 euros per month ( I have not subtracted the CAF ).
Hope these can help you resolve some puzzles.
pidan hua