https://fifpro.org/en/who-we-are/fifpro-members/fifpro-europe/the-lassana-diarra-judgement-explained-what-does-it-mean-for-footballers 

Indeed, following the Diarra judgment of the CJEU (4 October 2024), players can unilaterally break their contract, even without just cause, without now having to fear Fifa's disciplinary and financial reprisals.

On the basis of the judgment of the CJEU, partly ratified by Fifa, if a player breaks his contract without just cause, between 2 seasons, the international transfer certificate must be automatically issued, the financial compensation will be reasonably set by the competent national judge, on the basis of applicable national law (and it will be up to the old club to accurately demonstrate the existence of real damage), neither the player nor his new club can be imposed disciplinary sanctions and, finally, the new club will only be jointly and severally debtor of the financial compensation if the old club manages to demonstrate that it is effectively the new club that actively caused the termination of the contract.

The CJEU also ruled that the damage for which the former club can claim to obtain compensation cannot in any way include the unamortised part of the previous transfer.

It is advisable for any player who wishes to terminate his contract to contact a lawyer specialized in EU law and labor law.