Manchester United were last night facing the threat of a ban on signing players, just hours after Premier League rivals Chelsea were hit with sanctions barring transfers until 2011.
FIFA slapped an embargo on the Blues that prevents them from buying or selling players during the next two transfer windows because of their conduct over the transfer of Kakuta, 18, from French club Lens.
And United’s pursuit of a player from another French club could see the Old Trafford club hit with the same punishment.
Le Harve claim that Paul Pogba signed a pre-contract agreement November 2006 that committed him to a professional contract from his 16th birthday four months later, only for him to sign for United.
United have strenuously denied that they have broken any rules.
FIFA have so far failed to register Pogba's arrival at Old Trafford, although United insist they have done nothing wrong.
"It is complete nonsense," a spokesman for United said. "Everything has been done within UEFA guidelines."
However, Le Havre managing director Alain Belsoeur claims to have documentation showing United offered inducements for Pogba to join them and has vowed to include it in submissions to the world's governing body.
"We are still pursuing our case," Belsoeur told The Times. "It is a very serious case. We are confident that we'll win because it is in the best interests not just of our club but of sport.
"We spend five million euros [about £4.3million] on our academy every year out of a turnover of 12 million. euros. It is a huge investment.
"We do that to give a chance to our players to develop for our first team, not to be an academy for others.
"What is the point of investing in an academy if the players leave at 16? This is clearly a message from FIFA to protect the education system."