The 30-year-old Ashley-Cooper, who earned his 100th test cap this year, will join the Top 14 club on a two-year contract.
"I am delighted to join Bordeaux Begles (and) start a new chapter in my career and take on new challenges in the France championship," Ashley-Cooper said in a statement on the cub's website.
"I look forward to participating in the future of the club after the World Cup 2015 (and) I am extremely grateful for my career in Australia and I want to thank the ARU and the Waratahs for their support over the past decade."
The extremely versatile Ashley-Cooper was comfortable in the centres, on the wing or at fullback and will leave a large hole in the Wallabies backline when he joins the French club.
Several veteran players from both the Wallabies and their trans-Tasman rivals the All Blacks are expected to take up lucrative contracts abroad after the 2015 World Cup.
Both the ARU and NZRU have selection policies that preclude players based offshore from playing for the national sides.
