The Ulster fan allegedly punched by Trevor Brennan during Sunday's Heineken Cup tie has denied making obscene comments about the player's mother.
Toulouse player Trevor Brennan lashed out at an Ulster fan
Toulouse star Brennan says he regrets the incident but claims that he was provoked by taunts about his mother.
However, this was "categorically" denied by Ulster fan Patrick Bamford who said he had suffered a suspected fractured skull in the incident.
"I cannot accept that any circumstances can justify his violence," he said.
"There has been an attempt to justify the unexpected and still unexplained actions of Trevor Brennan which resulted in a serious assault on me.
"I categorically deny that at any point that I or anyone sitting around me was involved in sectarian abuse or in abuse of Mr Brennan about his mother.
"This recollection of events has been supported by witness statements taken at the time."
Bamford said that he was "saddened and disappointed" by Toulouse's response.
I love rugby, I love Toulouse and the supporters, but I love my family and my mother more than all that.
Toulouse have launched a robust defence of their player and Mr Bamford said that this could "only serve to send out a very negative message about the standards of behaviour acceptable among its players".
The ERC has also begun to investigate the incident and the former Ireland international is facing a lengthy suspension as a result of the incident.
"I didn't initiate it. That is the last thing I wished to do," said Brennan in a statement on Tuesday.
Former Irish international Brennan, who was on replacement duty for the match, had been warming up with his fellow Toulouse substitutes when he claims he was verbally abused by a group of Ulster fans.
The second-row forward then climbed into the stand and was involved in the incident with the Ulster supporter.
Brennan added he had a good relationship with Ulster fans but insisted that the provocation was unlike anything he had experienced before.
The statement continued: "I have always respected and I have always been respected by opposition supporters.
"I have often played against Ulster and not had these problems. I met their supporters days earlier and it was a true pleasure.
Ulster Rugby condemns Brennan for his actions which have tarnished the game of rugby football
"I love rugby, I love Toulouse and the supporters, but I love my family and my mother more than all that."
Brennan, a 33-year-old Dubliner who won 13 caps for Ireland between 1998 and 2001, later appeared in the game.
But he was yellow-carded after exchanging blows with Ulster's Australian lock Justin Harrison.
Ulster have already lodged a complaint with the ERC about the incident.
An Ulster statement said that that Brennan in the "disgraceful incident physically assaulted a member of the Ulster travelling support, Patrick Bamford".
"While Ulster Rugby's immediate concern was for the well-being of Mr Bamford, it would now urge the tournament organisers, the ERC and Stade Toulousain, to take immediate action to resolve this matter.
"Ulster Rugby condemns Brennan for his actions which have tarnished the game of rugby football."
The Ulster assertion that the chants directed at Brennan involved nothing more than disparaging comments about Brennan's Toulouse bar was backed by eyewitness, BBC Northern Ireland journalist Julian Fowler.