La Liga president Javier Tebas has said he does not fear being taken to court by France's Ligue de Football Professionnel (LFP) after he again hit out at Paris Saint-Germain.
Tebas, who in October accused PSG of "cheating economically," said this week it was "indecent" that they were allowed to compete in the Champions League because they were breaching financial fair play (FFP) rules.
Ligue de Football Professionnel president Nathalie Boy de la Tour wrote to Tebas and warned that his "relentless pursuit" of PSG could result in legal action being taken.
"I have a lot of respect for Tebas' work," Boy de la Tour told RMC Sports. "We are unafraid to admit that in Ligue 1, we are looking at what is going on in Spain and finding sources of inspiration.
"On the other hand, to each his own league. I find his relentless pursuit of PSG a bit out of place. I do not interfere with what is going on in Spain, or with Barcelona ... I will ask Javier Tebas to not barge into our league's affairs. Let the European authorities take care of these topics in question.
"It is not up to us, the league presidents, to criticise or to conspire against this club or that club. I have mailed him. The next steps may well be of the legal sort. He has not answered my mail yet, but I think that he will do."
Marca reported Tebas as saying: "I will reply and say that I don't have any problems showing and explaining how PSG cheats with regards to financial fair play.
"I'm surprised that a league as serious as the French one has not detected the problem, it seems strange to me. PSG's anti-competitive practices put at risk the balance of this industry.
"If they consider my comments to be defamatory, they can report me as soon as possible so we can prove in the courts that what we are saying is true."
Tebas infuriated his Ligue 1 counterpart with comments he made while speaking in a football debate earlier this week.
"What happens is that the PSG president is also the owner of beIN Sports, which is one of the potential buyers of the Champions League rights," El Mundo reported him as saying. "The conflict of interest is tremendous."
He accused PSG and Manchester City of "practising a club-state policy," saying the French champions' close links with Qatar and those of their English counterparts with the United Arab Emirates' ruling family resulted in unfair competition and meant sponsorship contracts had been overvalued.
UEFA opened an investigation into PSG's transfer dealings on Sept. 1, 10 days after Tebas had sent a letter detailing the difference between their commercial revenue and that of European competitors.
European football's governing body said earlier this month that its club finance monitoring panel would review a decision by investigators that PSG's accounts to June 2017 had complied with FFP rules.