Paris - Toulon defended their France international centre Mathieu Bastareaud on Monday after he used a homophobic insult against a Treviso player.
The French club said 29-year-old Bastareaud was "in no way homophobic" despite the incident involving Sebastian Negri in Sunday's European Champions Cup match.
Bastareaud, who has played 42 times for France, appeared to call Negri a "faggot" after an altercation in the final minutes of Toulon's 36-0 European Champions Cup win.
Video of the incident appears to show Bastareaud responding to a similar insult from Zimbabwe-born Negri.
The club said it was "convinced that Mathieu used these unfortunate words while agitated as can happen regularly in rugby and he is in no way homophobic".
"This kind of language should in no way allow people to cast aspersions about our captain who has always defended the rich diversity of individuals and who proves it every day in an eclectic Toulon squad," the club added.
Bastareaud tweeted an apology after the match, saying: "I apologise for my reaction to insults from the Italian player.
"I reacted badly by responding to his provocation, I'm truly sorry for the people I might have hurt."
European Professional Club Rugby, the organisers of the European Champions Cup, said it "had received a citing complaint against the RC Toulon player, Mathieu Bastareaud".
He is due to be heard by the EPCR on Wednesday and could be suspended.
Any suspension levied against Bastareaud could have an impact on his participation in the Six Nations, with France's opening game at home to Ireland on February 3.
Former England flyhalf Andy Goode condemned Bastareaud's comment in a tweet on Sunday, saying: "No place in the game for homophobia.
"Absolutely disgusting. I hope EPCR make an example of Bastareaud and ban him for a long time. Should throw the book at him."