The 23-year-old, who made 218 appearances for the Ligue 1 side, has passed a medical before signing a six-and-a-half-year deal with the Magpies.
"I am delighted to be a Newcastle United player," announced Sissoko, capped five times by France. "This is a massive club playing in the best league in the world, and I believe my style of play is suited to the Premier League.
"I have heard lots about how fantastic the Newcastle supporters are and cannot wait to get started.
"I am rising to a new challenge by coming here and want to firstly help the team improve this season and then progress after that."
A delighted Pardew added: "This transfer window has proved very productive for us and Moussa arriving is a massive plus for the club.
"He will bring drive and energy to the squad, he is a winner and that's why I'm especially pleased to have him with us.
"What all our signings this window bring is essential competition for places and that is great for the remainder of the season."
Sissoko is the fifth Frenchman to sign for Newcastle this month following the arrivals of Yoan Gouffran, Massadio Haidara, Mapou Yanga-Mbiwa and Mathieu Debuchy.