Mathieu Bastareaud could face a lengthy ban after the Champions Cup's organisers confirmed they were aware of an alleged homophobic slur made by the Toulon centre.
Television cameras appeared to show Bastareaud calling Treviso back row Sebastian Negri a "f---ing f-----" following an altercation in the 80th minute of his side's Champions Cup clash with Treviso.
European Professional Club Rugby (EPCR) must now wait for the match's citing commissioner to make a decision on whether to charge the France international.
Should Bastareaud face a disciplinary hearing then he would face a ban of at least six weeks, if found guilty. Under World Rugby regulations a mid-range suspension for "verbal abuse against a player based on... sexual orientation" is eight weeks, while if it is deemed a top-end offence then that would carry a ban of 18 weeks or more.
"EPCR has been made aware of an incident towards the end of today's RC Toulon v Benetton Rugby Champions Cup match," an EPCR spokesman said in a statement emailed to ESPN.
"As of now, the citing commissioner is considering the incident as part of his routine review of the match, and will make a decision when he has concluded his enquiries."
Bastareaud played three Tests for France during their November campaign -- his first since the 2015 Rugby World Cup -- but this incident puts his involvement in the Six Nations in some doubt.