Unlike the US, France does not have birthright citizenship so unless you or your spouse are a French national, your children born in France are not French citizens. If you live there legally long enough though you can apply for citizenship. Same as for permanent legal residents of the US who have lived here long enough.
My point is that I've lived here long enough (in 4 years, I'd have lived here longer than I lived in my home country) and I still have to wait an indefinite amount of time to become a permanent resident. I've been here 17 years and I'm still a 'temporary' worker. 15 years in the industry, >$500k/yr compensation and I've oversee a budget of $5 million.
A little technicality: persons born in France are automatically granted French citizenship at 18, providing that they are living in France at 18, and have lived in France for at least 5 years previously. These criteria tend to change a lot as this is a rather sensitive topic in France. Also sometimes an application is necessary, sometimes not.
An odd case: if both parents are foreigners, but one of them is born in France, then their children will automatically become French at birth (if born in France).
Then there are special rules for Algeria, as it was a part of France until 1962...
