The 26-year-old winger has left the Stadium of Light after a season and joins the Red and Blacks for the rest of the season
Wahbi Khazri has joined Stade Rennais on a season long loan from English Championship side Sunderland.
The Tunisia international joined the Black Cats from Bordeaux in January 2016, making 35 appearances in all competitions and scoring three goals.
He heads back to France after spells with Bastia between 2009-2014 before joining the Navy-and-Whites and spent two years Matmut Atlantique.
The winger becomes the eighth summer signing of the Roazhon Park, Rennes outfit joining Senegalese winger Ismaila Sarr and Malian right back Hamari Traore.
Christian Gourcuff’s men sit 19th on the French Ligue 1 log having just two points from four games and they will visit the Orange Velodrome to face Marseille in their next top flight game.