The court had been tasked with investigating the matter after former French national team midfielder Lassana Diarra challenged the International Football Federation (Fifa) and its regulations.
The background goes back ten years when Russian Lokomotiv Moscow broke with Diarra, claiming he had committed a breach of contract. Lokomotiv also demanded over 200 million kronor from the player, while Diarra instead wanted compensation from the club.
In the end, the Court of Arbitration for Sport (Cas) ruled in favor of the club, and Diarra was forced to pay damages of over 100 million kronor.
Diarra has claimed that Fifa's rules put obstacles in the way of his attempts to find a new club, as anyone who wanted to recruit him risked having to compensate Lokomotiv. Among other things, a transfer to Belgian Charleroi came to nothing.
And he now seems to be getting justice from the EU court, which finds that the transfer rules go against both the free movement of labor and competition law.
"The rules in question are such that they prevent the free movement of professional football players who want to develop by starting to work for a new club," the court says in a statement, according to AP.
Lassana Diarra has sued both Fifa and the Belgian Football Federation for lost income of nearly 70 million kronor, which he missed out on when the Charleroi transfer did not materialize.
The case is ongoing in Belgium, pending the EU court's ruling.