Suspended FIFA president Sepp Blatter said Real Madrid and Atletico Madrid should face similar sanctions to that of Barcelona if they are found guilty of transfer irregularities.
FIFA are investigating La Liga duo Madrid and Atletico over the signings of underage players.
Barca were handed a transfer ban by FIFA in 2014, having failed to comply with rules on signing international under-18 players.
The La Liga champions were banned from registering players for two transfer windows, though they still managed to sign Arda Turan from Atletico and Aleix Vidal from Sevilla, despite not being able to register them until January.
With Madrid and Atletico now being investigated for their recruitment of young players, Blatter - who has been suspended for an alleged "disloyal payment" made to UEFA president Michel Platini - believes the Spanish capital clubs should be punished if they are found guilty.
"Effectively the Disciplinary Committee of FIFA has opened two separate files to Real Madrid and Atletico Madrid for the same offenses committed by FC Barcelona," Blatter told Mundo Deportivo.
"They are closed, but I do not know what the sanctions are because they are independent commissions and I am currently banned... I can't even walk inside FIFA.
"If Barcelona were sanctioned for breaking the FIFA regulations, and the two Madrid clubs have committed the same offences, then the normal thing would be to give them the same sentence."
"Maybe Barcelona made a mistake starting this war against FIFA. It would have been better to open a dialogue, a path that always works better in football."
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