Antoine Griezmann's controversial move from Atletico Madrid to Barcelona, will be investigated by the Spanish Football Federation, the UK Mirror reports.
Griezmann joined the LaLiga champions earlier this week, after turning them down last year.
Barca claim to have activated a clause in the Frenchman's contract, which allowed him to leave for €120million from July 1.
But Atletico claim their rivals began negotiating with Griezmann in March, meaning they are owed another €80m due to a previous clause in his contract.
The club themselves are yet to make an official complaint, but the federation has opened a file on the move regardless.
Barcelona have consistently denied any wrongdoing with club president, Josep Maria Bartomeu, saying: "I have spoken to them, but I do not think there is any proof, because there is no evidence of anything.
"I understand everyone defends their interests and I've spoken to [Enrique] Cerezo [Atletico president], but I don't see that the case can evolve in a positive way for them. There's nothing.
"We contacted Griezmann after he made the video saying goodbye to the fans, there was nothing in March."
The player himself added: "Regarding Atletico, it's a pity. I went to see them on purpose so they would not be caught off guard and could prepare for the future."