Barcelona will reportedly face a legal investigation from the Spanish Football Federation in response to the acquisition of Antoine Griezmann from Atletico Madrid.
The La Liga champions finally secured the signature of Griezmann for a fee of £108m earlier this week after initially establishing their interest in the Frenchman last summer.
The club claim that the deal went through after activating a clause on Griezmann's contract which allowed him to leave for £108m on July 1.
However, according to The Mirror, Atletico believe that since Barcelona started negotiations for the forward in March, they are owed another £71.8m due to a previous clause in his contract.
Atletico are yet to lodge an official complaint, but the federation - who prosecuted Barcelona following their acquisition of Neymar in 2013 - are nonetheless set to open a file on the move.
Diego Simeone's side have splashed out £116.8m on striker Joao Felix as a replacement for Griezmann, who had spent five seasons in the Spanish capital.