Visa question for Americans

Hello, I'm new to the forums and I'm trying to figure something out with my visa. I'm here on a short term contract to work as a teaching assistant, but frankly I'm not all that happy with placement and some other issues with my school. However, I would love to stay in France even if this position doesn't work out. I was wondering about the technicalities of changing jobs while on this type of visa, since I want to look for an au pair position. I can't seem to figure out if I would have to apply for a new visa or if my temporary visa would allow for a change of occupation and a possible extension.