The highly-rated holding midfielder has signed a five-year contract with the Magpies.
“After eight fantastic years at Lens, I have stagnated. I needed a change of air. I am not afraid to leave for abroad,” he told L’Equipe.
“I have had contact dating back some time and I visited the facilities there last week. I even trained with the reserve team.
“The leaders of the club told me about their plans and that they will rely on me for next season.
“For my part, I intend to give everything to develop in the Premier League.
“I already discussed things with Hatem Ben Arfa and Cheick Tiote and they encouraged me and welcomed my signature.”
Everton, Atletico Madrid, Rennes and Le Mans were also keen on signing the youngster.