changing jobs on a french work permit

[jfc]

Hello all out there.
I've been working in a restaurant in France on a stagiare work permit for 1 1/2 years. I've now gone through all the proceedures with my employer to change my status to a full work permit and carte de sejour. The process will be finished within 2 weeks. But there are many problems at thhe restaurant now.
My question is, may I change restaurants before my papers are finished and apply the papers to another? (This I doubt) Hence 2nd question is once I start at the restaurant, how long until I have the right to change restaurants if I even have this right at all?
Thank you very much. I'm not looking forward to commiting to a potential of multiple years in a bad situation.
Jon