The bitter dispute between Kylian Mbappe and his former club Paris Saint-Germain reached the French Labour court on Monday for a tense hearing in which the France striker claimed 263 million ($304m) and the club responded by demanding he pay them 440m euros.
Both sides offered a long shopping list of grievances with price tags attached.
PSG said they are basing their figure in part on a botched 300m-euro transfer to Saudi club Al Hilal which the player refused in June 2023 and its aftermath.
Mbappe left for Real Madrid on a free transfer when his contract expired the following summer.
"We are indeed claiming 440 million euros," Renaud Semerdjian, one of the seven lawyers representing the Parisian club, told AFP after the hearing.
Semerdjian said the figure included lost transfer revenue, compensation for damage to the club's image and for what the club said was a breach of an agreement they made with Mbappe after he refused to move to Saudi Arabia.
Mbappe, absent on Monday but represented by four lawyers, says he made no agreement in 2023 to waive any money from the club.
The 26-year-old striker initially filed a complaint in June over the way he was treated by PSG at the start of the 2023-24 season.
Mbappe argues that he was sidelined by the Qatari-owned club and made to train with players the club were trying to offload after refusing to agree a new contract.
It is a widespread practice that in France prompted the players' union to lodge a complaint last year.
Mbappe was not invited to take part in PSG's 2023 pre-season tour of Asia and missed the first game of that season but was later recalled to the team after holding talks with the club.
He is also claiming PSG are applying the wrong French legal classification to his contract.
After seven seasons with PSG he then joined Real Madrid where he earns a reported annual salary of 30m euros.
He scored 256 goals in 308 games for PSG but the club won the Champions League for the first time last season following the striker's departure.
The tribunal will take several weeks to reach a decision which is expected on December 16.
