Fifa are set to investigate Paul Pogba’s transfer to Manchester United, according to reports in France.

The Frenchman moved to the club last summer for £89m to become the most expensive player in the history of the sport.

Fifa have asked United for "clarification on the deal", the AFP news agency says, though it remains unclear what details are under scrutiny.

Manchester United's best XI with Paul Pogba Show all 11 1 /11 Manchester United's best XI with Paul Pogba Manchester United's best XI with Paul Pogba David De Gea Has been Manchester United’s best player for the last four or five seasons and, after having a move to Real Madrid collapse last summer he is now more important than ever. He saved United repeatedly under David Moyes and Louis van Gaal and will hope under Jose Mourinho that there is less to do. Getty Manchester United's best XI with Paul Pogba Matteo Darmian A good player whose first season at Old Trafford was badly affected by injuries, Darmian should improve next year under the guidance of Mourinho. He has played for a similarly prescriptive coach for Italy in Antonio Conte and will provide exactly what Mourinho wants in the role. Getty Manchester United's best XI with Paul Pogba Chris Smalling One of United’s most improved players under Louis van Gaal, he established a leadership and consistency that he had lacked before. Now he is near the peak of his powers and gives Mourinho someone to build around at the back. Getty Manchester United's best XI with Paul Pogba Eric Bailly The first of Mourinho’s summer signings, the £30million man from Villarreal has looked good in pre-season already. Will need to adjust to the speed of the Premier League but looks well equipped to do that and form a strong pairing with Smalling. Getty Manchester United's best XI with Paul Pogba Luke Shaw Had his last season ruined by a broken leg against PSV Eindhoven and without him United lacked pace and width down the left. Mourinho will like his competitive attitude and Shaw will surely feature in Sam Allardyce’s England squads soon enough. Getty Manchester United's best XI with Paul Pogba Morgan Schneiderlin Mourinho teams always have a midfield anchor, what he calls a ‘number 6’, and there is no-one better suited to the job at United now than Schneiderlin. Did not play as much as he should have done last year but that should change now. Getty Manchester United's best XI with Paul Pogba Paul Pogba The big issue for Mourinho will be where to fit in the £100million man. There will be times when he plays alongside Schneiderlin in a 4-2-3-1, when United can afford to attack more, and others where he is pushed further up with two midfielders behind him. Finding the perfect platform will be Mourinho’s hardest task. Getty Manchester United's best XI with Paul Pogba Henrikh Mkhitaryan Not the highest profile summer signing at Old Trafford but a technical wizard who excelled in his three seasons at Borussia Dortmund, which is why Arsenal wanted him too. Likelier to be on the right of a 4-2-3-1, where he will provide creativity and intelligence. Getty Manchester United's best XI with Paul Pogba Wayne Rooney Mourinho said very clearly that Rooney will not play in midfield this season for United, so he will have to partner with Zlatan Ibrahimovic up front. Rooney will likely start as a second striker or number 10, but has a job to prove that he is still sharp enough for the job. Getty Manchester United's best XI with Paul Pogba Anthony Martial Never looked weighed down by his fee last season and showed pace, class and natural calm in front of goal. Likely to continue on the left this season where he will provide pace on the break, as long as he does the defending Mourinho demands too. Getty Manchester United's best XI with Paul Pogba Zlatan Ibrahimovic One final challenge for the big Swede who has won the league everywhere else he has played. Still has incredible strength and skill, even if he will be one of the slower strikers at the top this year. Just needs to find a way to be a focal point for his team-mates. Getty

This follows reports that the midfielder's agent, Mino Raiola, is set to make £41m from the transfer. Leaks suggest that Raiola acted on behalf of Manchester United, Juventus and Pogba, contravening Fifa's rules governing transfers, according to French outlet Mediapart.

In a recently published book, ‘Football Leaks: the Dirty Business of Football’, Raiola's extraordinary earning power is laid bare.

According to the book, based on the research of Der Spiegel journalists Rafael Buschmann and Michael Wulzinger, the so-called 'super-agent' was handed a £23m cut of the initial transfer fee and will receive five instalments totalling £16.39m over the course of Pogba's five-year contract.

The 24-year-old started his career with the English club but made just three appearances in the Premier League before heading to Italy, after an apparent falling out with then manager Alex Ferguson.

Pogba provides laughs as key players return to Man United squad

The Frenchman went on to flourish in Serie A, winning four league titles with Juventus between 2012 and 2016.

Pogba also appeared in the 2015 Champions League final, which Juventus lost 3-1 to Barcelona.

At the same time, the powerful midfielder made himself a mainstay of the French national team.

He made his debut in March 2013, just a week after his 20th birthday, in a World Cup qualifier against Georgia.

He also featured as part of the 2014 French World Cup squad and was named the tournament's best young player.

Pogba's performances at the 2016 European Championship helped attract the attention of his former club Manchester United, under new manager Jose Mourinho.

After a protracted transfer saga, lasting several weeks, Pogba eventually signed for United last August and has so far appeared in almost 50 league and cup games this season.