Barcelona and Real Madrid must pay millions of Euros in extra tax after the European Court of Justice found they benefited from state aid.
The verdict from the European Union’s top court settles a long-running legal battle involving four of Spain’s leading football clubs.
Athletic Bilbao and Osasuna are the other teams facing bills for unpaid tax.
The development is another blow for Barcelona, whose offices were searched by Catalan police this week in connection with a separate investigation.
Former Barcelona president Josep Marian Bartomeu and the heavily indebted club’s current chief executive Oscar Grau were arrested.
The state aid case relates to tax breaks afforded by Spain to certain member-run clubs.
Barcelona, Real Madrid, Athletic Bilbao and Osasuna were treated as non-profit organisations and paid five per cent less tax than other teams for more than 20 years.
This gave them an unfair advantage over their rivals, the ECJ ruled.
A lower EU court backed the clubs’ position in a 2019 decision, but the ECJ said that had now been “definitively rejected”. Repayments are likely to be capped at €5m per club.
The police investigation into Barcelona relates to allegations some board members ordered a social media smear campaign of their enemies.
Bartomeu has denied the claims and an external audit cleared his regime last year.