Kylian Mbappé's lawyers have sent a final notice to Paris Saint-Germain to request that the club pay the wages that he believes they owe him, a source has told ESPN.
The notice arrived at the club's offices in Paris last week. Mbappé, 25, believes that the club owes him almost €100 million ($106.8m) in unpaid wages and bonus payments.
A source confirmed to ESPN that the French champions are yet to pay him his April, May and June salaries, as well as his February bonus.
PSG believe that the player agreed in August to to write off some of the money that he was due in order for the club to reduce the financial impact of his departure at the end of his contract in June, a source said.
However, a source added that there was no written and signed version of this agreement and that this is at the heart of the dispute. PSG, who do not intend to respond to the formal notice, plan to act on what they believe was agreed.
Sources said that Mbappé is of the opinion that PSG's decision to not play him regularly from February to May after he told them he was leaving the club cancelled their agreement and that he wants all the money that he says he is owed.
It is thought that it may be necessary for both parties to argue their case in front of a tribunal in order to achieve a resolution.
The France captain spent seven years in the French capital before joining Real Madrid as a free agent on June 3.
The dispute with his former club was a factor that contributed to his comments on June 5 about being unhappy with PSG.
Mbappé said certain people at PSG made him "unhappy" in his first news conference since completing his move on a free transfer to Real Madrid.
Sources have told ESPN that PSG felt he was being "ungrateful" in his comments and added that the club will not reimburse him €80 million in wages and bonuses in an effort to recoup the money for his departure.