The 18-year-old has agreed a five-year contract at St James' Park and snubbed interest from Everton, Atletico Madrid, Rennes and Le Mans.
Mehdi Abeid: "After eight fantastic years at Lens, I have stagnated. I needed a change of air. I am not afraid to leave for abroad.
"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."
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