It has not been confirmed which part of the deal FIFA will investigate.
Yesterday, it was revealed that Mino Raiola, the super-agent and representative of Pogba, is set to make £41m off the world-record deal.
The Frenchman left United in 2012 as a free agent, after Raiola reportedly told then United boss Sir Alex Ferguson that the offer the Scotsman presented his client was something that his "chihuahuas wouldn't sign."
Since his return to the club last summer, Pogba has played well below the lofty expectations that were placed upon him after his move. The midfielder has only managed 4 goals and 3 assists in the Premier League this season, and has not scored a goal in 2017.