Passports belonging to Toulouse captain Mauro Cetto, Marseille defender Renato Civelli and Bordeaux duo Fernando Cavenaghi and Diego Placente - all of whom claim dual nationality - are being looked at, according to French daily L'Equipe.

The French league have contacted Italian authorities about the issue as a preventative measure.

The good faith of the players and their clubs is not being challenged, but the league are looking into the matter in anticipation of potential protests by rival Ligue 1 clubs at the end of the season.

"For the moment, there is no panic," Jean-Pierre Hugues, the French league's director general, told L'Equipe.

"We are waiting for the Italian authorities to come back to us.

"But in any case, if these players one day lost their dual nationality, the clubs concerned would not exceed their quota of foreign players and that could not call into the question the championship."

Toulouse have released a statement confirming Cetto's Italian nationality.

"The grandparents on his mother's and father's side are Italian and the player, according to Italian laws, has Italian nationality," it read.