Working Visas in France (Paris)

Hi, I am in a dilemma. I have started to work for a private school in France who have supported me with my working visa. My Visa stamp was issued in Australia and I am waiting for OFII for contact me and to have my medical. Unfortunately, I am not 100% happy with the job - location, pay, etc.
I don't know my resignation period and I am not sure how 'resigning' will affect my Visa. Any ideas / suggestions???