The EU Commission confirmed receipt of the complaint. "The Commission is assessing the complaint under its standard procedures," a spokesperson said.

Any transfer of Messi from Barcelona to Paris would constitute a distortion of competition with other national leagues, the complaint claims, and would be detrimental to Barcelona fans.

Meanwhile, in more bad news for Barca, their new signing Sergio Aguero will be out until mid-October due to a calf injury.

The 33-year-old striker, who was signed in July as a free agent from Manchester City, suffered a right calf injury in Sunday's training session before Messi gave a farewell speech at the Camp Nou.

Aguero was unable to make his debut in Barcelona's 3-0 win over Juventus in the Gamper trophy.

"It's a pity Aguero got injured and could not play 30 minutes at the Gamper," Barca coach Ronald Koeman said after the game. "It's a setback as he was training and can bring a lot to the team with his quality up front."

Barcelona will begin their La Liga season at home against Real Sociedad on Sunday.

With input from Reuters