The 28-year-old, who was at Le Mans from 2005-08 and played under Rudi Garcia, will join up with his former manager.
"I join an ambitious club and I'm happy to be reunited with Rudi Garcia, a coach who helped me improve a lot," Basa said in a statement.
Lille had been looking for a centre-back since France defender Adil Rami left for Valencia at the end of the season.
