UEFA has launched an investigation following allegations Barcelona made payments to a former vice-president of Spain's referees' committee.
Reports last month claimed the club paid companies owned by Jose Maria Enriquez Negreira €7million (£6.2m) between 2001 and 2018.
Negreira was the vice-president of the Spanish football federation's refereeing committee from 1993-2018.
Barca could face corruption charges in court over the allegations after Spanish prosecutors filed a complaint earlier this month.
Now football's European governing body has announced it will also be investigating the claims.
A statement on Thursday read: "In accordance with article 31(4) of the UEFA disciplinary regulations, UEFA ethics and disciplinary inspectors have today been appointed to conduct an investigation regarding a potential violation of UEFA's legal framework by FC Barcelona in connection with the so-called 'Caso Negreira'."
Barca have previously denied wrongdoing. A statement said they had paid an external consultant for "technical reports related to professional refereeing", arguing it was common practice in the game.
President Joan Laporta said: "Barca have never bought referees nor influence. That was never the intention and that has to be clear. The facts contradict those that are trying to tell a different story."
