The Guingamp midfielder had been linked with a Premier League switch, but the report claims he'll join Marseille after the Ligue 1 giants reached an agreement for his transfer.
Chelsea and Arsenal scouts watched the 20-year-old help Guingamp to promotion from Ligue 2 last season.
Monaco were also watching his development closely, but the trio looked to have been beaten by Marseille after Guingamp reached an agreement for a sale.
The report claims he'll complete his medical at the Stade Velodrome on Thursday before putting pen to paper on a five-year deal.
The midfielder was called up for the France under-21s earlier this summer, capping a memorable 12 months for the youngster.
Marseille, who finished runner-up in Ligue 1 to Paris St Germain last season, are looking to strengthen their central midfield.
Reports have claimed they're keen to bring Queens Park Rangers midfielder Joey Barton back for another season.
They've already been quite busy in the transfer market, snapping up Dimitri Payet from Lille and Benjamin Mendy from Le Havre.
Both French stars were linked with Premier League moves at one stage last season, but have opted to move to the south coast of France.