Chelsea have begun disciplinary proceedings against midfielder Enzo Fernandez after he posted a video on social media that the French Football Federation said included an alleged "racist and discriminatory" chant.
On Tuesday the FFF said it would file a complaint to world governing body Fifa over the video featuring a song sung by some of the Argentina squad about France's black players.
Fernandez's Chelsea team-mate Wesley Fofana, who has one cap for France, posted an image of the video on Instagram, describing it as "uninhibited racism".
Fernandez - a £107m British record signing in February 2023 - said he is "truly sorry" for the video he posted as Argentina celebrated winning the Copa America.
Fifa is also investigating the video, in which several members of the Argentina squad take part in a song originally sung by Argentina fans questioning the heritage of France's black and mixed race players.
Chelsea have seven France players who are black or mixed race in their first-team squad - Fofana, Axel Disasi, Benoit Badiashile, Lesley Ugochukwu, Christopher Nkunku, Malo Gusto and Malang Sarr.
"The song includes highly offensive language and there is absolutely no excuse for these words," said Fernandez.
"I stand against discrimination in all forms and apologise for getting caught up in the euphoria of our Copa America celebrations.
"That video, that moments, those words, do not reflect my beliefs or my character."
A Chelsea statement read: "We acknowledge and appreciate our player’s public apology and will use this as an opportunity to educate.
"The club has instigated an internal disciplinary procedure."
The FFF will contact the Argentine Football Association (AFA) about the live video posted on social media by Fernandez after Argentina beat Colombia 1-0 in the Copa America final on Sunday.
A statement from the FFF, external said president Philippe Diallo "condemns in the strongest terms the unacceptable and discriminatory remarks that were made against the players of the French team".
It added: "Faced with the seriousness of these shocking remarks, contrary to the values of sport and human rights, the president of the FFF decided to directly appeal to his Argentine counterpart and Fifa and to file a legal complaint for racially offensive and discriminatory remarks."
The Argentine FA has been approached for comment.
France beat Argentina in the last 16 of the 2018 World Cup, and Argentina beat France in the final of the 2022 World Cup.
A Fifa spokesperson said they were "aware of a video circulating on social media" and "the incident is being looked into".
They added: "Fifa strongly condemns any form of discrimination by anyone including players, fans and officials."
Chelsea said they find "all forms of discriminatory behaviour completely unacceptable".
They added: "We are proud to be a diverse, inclusive club where people from all cultures, communities and identities feel welcome."
Fernandez's Chelsea team-mate David Datro Fofana urged action by everyone in football in the "fight" against racism.
"The football that I like is multi-ethnic," posted the Ivorian forward on Instagram.
"Racism in all its forms should be condemned in the strongest possible terms. These acts have no place in football or even anywhere else.
"This fight really needs to be taken seriously be everyone in this sport."
Fofana is currently training with Chelsea after his loan spell with Burnley last season, while fellow Blues striker Nicolas Jackson has also published a post on Instagram in support of Fernandez.
Jackson's post showed the Argentina midfielder playing with a young black child during the club's pre-season US tour last year.
Former Argentina midfielder Javier Mascherano, who is the coach of the nation's Olympic football team, said the video was "taken out of context" and his country is "totally inclusive". The 40-year-old, whose side will play at this summer's Games in Paris, also said Fernandez is a "great guy".
Anti-discrimination charity Kick It Out, meanwhile, said the video is "unacceptable".
"We stand with and show our full support to Wesley Fofana after he responded publicly and brought it to wider attention," it added.
"Several players are seen singing the song, which means there will be a wider impact on team-mates and fans at other clubs.
"We call upon all relevant clubs, the Argentina federation and Fifa to address this concerning issue with empathy, sensitivity and understanding.
"Responses to these incidents cannot start and end with an apology. More important is the action taken afterwards to ensure players are educated and held accountable, both in England and on a global scale."
Those comments were echoed by fellow anti-discrimination organisation Show Racism the Red Card, which said "words are not enough".
"The racism by the Argentina players is abhorrent, disgraceful and, to record it on social media, it's unbelievable to think it was amusing or even they would get away with it," said chief executive Ged Grebby.
"It's good they haven't but we want to see action taken, rather than players saying just they are sorry. That's not good enough.
"The damage has been done. Not just to black players in the Premier League but black players in our society.
"Words are not enough and if Chelsea are serious about anti-racism education we urge them to contact Show Racism the Red Card and get this player to come and work with us in schools.
"It would make a huge impact. Rather than banning this player for whatever number of games, let's get him involved in an anti-racism programme, a positive programme, with Show Racism the Red Card."
