The 25-year-old has signed a five-year contract with the Magpies.
“This is a fantastic move for me,” he told Newcastle’s official website.
“I have enjoyed great times with Lille but the time is right now to test myself against the best and playing for Newcastle United in the Premier League does just that.
“My first impressions of the club and the city are that it is a lovely place and the stadium is magnificent.
“Now that I have signed I am looking forward to meeting the rest of the team, working with (manager) Alan Pardew and his staff, but most of all playing for Newcastle United and their supporters.”
“We are delighted to have signed Yohan on a five-year contract,” said Newcastle boss Alan Pardew.
“He has a first-class pedigree having proved himself at the top level in France, both for his club and the national team.
“He will add great quality to our squad and I am really looking forward to working with him.”
