On my Basque (French) side I got back to March 10, 1340. Before that time there were no surnames in the town.
What made French research hard was the fact that almost every son named a son after the family patriarch. So there were a dozen Jacques per generation. Of course only the eldest of a huge family got any inheritance, so being related to the Sieur de Bienvilles 4th son does not get you any points with 5th cousins in the social register.
I think the oldest name I got was that female I mentioned, and that was the 1200s.