Atletico Madrid are demanding that the transfer of Antoine Griezmann to Barcelona be revoked according to La Liga president Javier Tebas.
The France international joined the Catalans on July 12 after they paid his €120 million (£107m/$134m) buy-out clause.
But Atleti are objecting the transfer, claiming they are still owed more money as a deal for the forward was agreed before his release clause dropped by €80 million midway through this summer's transfer window.
La Rojiblancos have now petitioned The Royal Spanish Football Federation (RFEF) to prevent Antoine Griezmann from playing for Barcelona next season.
And according to Spanish top-flight league President, an investigation into the transfer has been opened.
"Atletico wrote to us asking if we could block Griezmann's license in Barcelona," Tebas told Spanish radio station Onda Cero.
"It is possible to do it. A mechanism has been put in place and the authorities will have to resolve the situation. I have no element of judgment."
The world Cup winner has already played a pre-season game for his new club, lining out from start in the 2-1 defeat to Chelsea in the International Cup.
Joao Felix was brought in from Portuguese club, Benfica as the direct replacement for Griezmann.