Changing visa type - Z to S?

Hi,
I have been living and working in China for nearly three years on a Z type. This summer I plan to quit my job and get a S type sponsored by my wife who's on a Z one - I'm American and she's French. I am eligible for the S1 type, correct? Is it possible to apply for the S one within China or will I have to leave? If I have to leave, can I apply for the S type from France, as my wife is French and we were married in Europe with a European issued marriage certificate?