Found that:
LuckyLoc : Location de voitures et utilitaires à 1 euro
It's in French, got the link through a website I use to buy train tickets for years. They talked about it on the French tv.
Basically it is low because it seems to be cheaper for the car rental companies to do that to bring a car from point A to point B.
I talked to them saying that I can only use a Us credit card to pay, I have a French drivers license in addition to my Us one and did not ask if they would accept a Us one.
As soon as I fly back and use it I will let you know.