The 19-year-old has agreed to terms with the Ligue 2 outfit and will wear the number 15 shirt as he looks to secure more senior game time.
Traore is yet to feature for the Red Devils' first-team but made 14 appearances for their Premier League 2 outfit this season where he scored four times.
The talented Frenchman moved to Old Trafford in 2017 after coming through Paris Saint-Germain's academy and recently declared his desire to step up to a first-team environment.
"I have become a more complete player in three years," Traore told RMC Sport.
"I have put on a fair amount of muscle and I am stronger physically, I have become better tactically...I think that I am a player who is ready for professional football.
"In terms of how I have progressed, I am happy with my three years. But at the same time I imagined that I would already be a bit further ahead. Playing and training more regularly with the first-team squad.
"Now, these three years must enable me to play at the professional level. I’ve acquired a background at the youth academy in Manchester that I want to use at a higher level now.
"I hope that happens in Manchester, if not then why not go and get playing time elsewhere. But if I leave, it is for a first team. I do not want to leave Manchester to be in the same situation elsewhere."
Traore has previously been billed as the next Paul Pogba and the teenager revealed the France star has taken him under his wing.
"I speak a bit with him, notably when I go and train with the first team," Traore said. "He is a bit like how he is on social media, a bit crazy! He does look after the Frenchies."
Traore is currently contracted to Old Trafford until 2021 making this next season a decisive one for the young midfielder.
Manchester United face Sevilla in a blockbuster Europa League semi-final on Sunday night with the Red Devils desperate to claim their first trophy since 2017.