Kylian Mbappé Tells P.S.G. He Will Leave Club Next Summer

First it lost Lionel Messi. Now Paris St.-Germain, the Qatar-backed French soccer champion, could be facing the loss of another of the game’s biggest stars: Kylian Mbappé.

Mbappé, one of the world’s most marketable athletes and the cornerstone of the club’s plans to rebuild its identity around a core of top French talent, has informed P.S.G. in a letter that he will not renew his contract when it expires next June, according to an executive familiar with the discussions between Mbappé and P.S.G. The executive was not authorized to speak publicly about the talks, given their sensitive nature.

Mbappé’s decision could force P.S.G. to consider a move it would prefer to avoid: selling Mbappé’s playing rights as soon as this summer, rather than risk losing him for nothing when his deal expires next year. If the club does entertain offers for Mbappé, P.S.G. could expect to fetch a price well in excess of $200 million that might eclipse the world record for a player.

P.S.G.’s top officials were taken by surprise by Mbappé’s letter, according to the executive, and learned of it after first being contacted by a French news outlet claiming to have received a copy before it was sent to the club. A spokeswoman for Mbappé did not respond to a request for comment. Representatives of P.S.G. also did not comment on the letter or how the club was informed of Mbappé’s intentions, which were first reported by the French sports newspaper L’Equipe.

P.S.G. had faced a similar crisis over Mbappé’s future only last summer, as the striker, then out of contract, had been poised to join Real Madrid before a last-gasp effort, and cold hard cash, persuaded him to sign a new deal that kept him in Paris.

That contract was a two-year deal, with a player option for a third year. In his letter, a copy of which was seen by The New York Times, Mbappé has told the team that he will not exercise the option, meaning his current contract, and most likely his association with P.S.G., will end after the coming season — unless P.S.G. finds a team willing to pay to acquire him sooner.

And once again the most likely destination for Mbappé is Real Madrid, the Spanish club that was Mbappé’s favorite when he was a boy, and which offered him the richest contract in its history a year ago.