Mathieu Debuchy: "It is great to become a Newcastle United player.
"After many great years at Lille I felt I was ready for a new challenge, and cannot wait to play for such a big club in the best league in the world.
"I hope I can bring something fresh to the team and help us get up to the highest possible position in the Premier League this season."
Debuchy has not signed in time to feature in the weekend's FA Cup clash with Brighton, with Vernon Anita set to stand-in, as Simpson is unavailable through injury.