The 21-year-old centre-back, who has represented France at underage level, has committed himself to les Rouges et Blanc until 2017 following his move from ValenciennesMonaco have further strengthened their squad with the acquisition of defender Nicolas Isimat-Mirin from Valenciennes for an undisclosed fee.
|3/1||Monaco are 3/1 with bet365 to win Ligue 1
"This is really a big thrill for me to get involved with Monaco," Isimat-Mirin told the club's official website.
"I feel a lot of joy, but also great anticipation. I'm looking forward to Monday for the resumption of training.
"This team's project is fantastic and I will give everything to prove that I deserve to be part of it."
Monaco have been very busy in the transfer window already, having already made a number of notable signings, including that of Radamel Falcao from Atletico Madrid.