The 23-year-old joined Newcastle on loan in September before breaking his leg the following month.
He has signed a contract until 2015.
“He’s obviously a top player and he’s shown that in France, at international level and in his short time here at Newcastle,” Newcastle manager Alan Pardew said in a club statement.
“Once he’s back fit, I have no doubt he’ll confirm just what a superb player he is.”
Newcastle, 10th in the league after 20 games, did not give details of the transfer fee.