If you want to teach in France in states school you need at least a maitrise (4 years of french university studies).
In private schools it depends.
I've been looking for jobs as french or english teacher for adults as I have diplomas for both, TEFL and FLE. For english you need to be a native speaker. For french you need the equivalent of the maitrise or the new diploma which is the same. I only have the licence level and most of the "alliance francaise" require more.
Anyway there are jobs so keep on trying and don't give up afer a few rejections. Some areas are more in need than others and France is big!