What about a person born in france whose parents are both american citizens?

There are only a few cases in which the sole fact of birth on French soil qualifies a child to automatically receive French citizenship. Pursuant to articles 19 and 19-1 of the Civil Code, those cases include

any child born in France of an unknown father and mother,

any child born in France of stateless parents, and

any child born in France for whom foreign laws on nationality do not permit in any way the conveyance of the nationality of either one of the parents to him/her.

The child, however, will be considered to have never acquired French citizenship if, before reaching the age of majority, one of his parents is found (in the case of a child born of an unknown father and mother) and he acquires the parent’s citizenship, or the foreign citizenship acquired or possessed by one of the parents is conveyed to him or her.

Finally, a child is French if born in France to at least one parent also born in France. If only one parent was born in France, the child may renounce French citizenship.

I believe that the child would be French since it wasn't born in America no matter if his / her parents are American.