Lyon paid Forest 10 million pounds ($12.74 million) for the loan transfer of the player until June 30th, the Ligue 1 side said. The deal includes a purchase option at an additional 15 million pounds plus a maximum of three million pounds in add-ons.
Mangala, a youth product of Belgium's Anderlecht, joined Forest from Bundesliga side VfB Stuttgart in 2022 and made 47 Premier League appearances, scoring two goals.
He made his Belgium debut in 2022 and has earned 12 international caps.