Spanish club Atletico Madrid have been fined, FIFA said on Friday, for signing a player to a contract that allowed third-party ownership, which is banned by world football’s governing body.

Atletico, who beat Real Madrid to win the European Super-cup on Wednesday, must pay 52,000 Swiss Francs for ” entering into a contract that enabled a third party to influence the club’s independence in employment and transfer-related matters and entering information in the international Transfer matching System,” a FIFA statement said.

The player in question was not named.