UEFA's Financial Fair Play laws have been challenged by a top European football lawyer.
Jean-Louis Dupont - part of the legal team that won the landmark Bosman ruling in the 1990s and who led the case that forced FIFA and UEFA to compensate clubs for players on international duty - claims FFP will breach European competition law.
The European Commission have agreed to the new laws but Dupont says the European Court of Justice may take a different view.
Dupont said: "Some of Europe's biggest clubs are, unsurprisingly, the loudest supporters of rules that entrench their dominance.
"The time is right for a strong reminder from the EU's anti-trust authorities that football, like any other multi-billion euro industry, must comply with the law.
"As an agreement whereby industry participants jointly decide to limit investments, FFP likely constitutes collusion and hence a violation of EU competition law. FFP may also infringe other EU freedoms such as the free movement of workers and services.
"Even if FFP were sufficiently legitimate and necessary to justify its distortions of EU principles, UEFA would need to convince the EU's judges in Luxembourg that FFP is the least restrictive means of achieving its aims. This seems unlikely."