[PeterPrinciple]

According to this it was U510 that became the French submarine

http://uboat.net/boats/u510.htm

[Seizethecarp]

http://en.wikipedia.org/wiki/German_submarine_U-510

Post war

U-510 was captured by American forces at Saint-Nazaire on 10 May 1945. Awarded to the French in 1946, she was commissioned into the French Navy, and renamed Bouan (S.612) on 24 June 1947. She served until struck on 1 May 1959, renamed hull Q.176 on 23 November 1959, and was broken up in 1960.[4]