Toulouse forward Trevor Brennan has announced his retirement from rugby union with immediate effect.
Brennan clashed with fans during the match against Ulster
The 33-year-old, who won 13 Ireland caps, had originally intended to quit at the end of the current campaign.
His decision comes ahead of an ERC disciplinary hearing arising from an incident in the Heineken Cup match between Toulouse and Ulster in January.
Brennan, currently suspended, entered a section of the crowd housing Ulster supporters and struck one of them.
He and his legal advisers had sought an adjournment of the hearing, pending a possible civil case in France, as they argued it might prejudice his case.
The IRB requested that the French Federation suspend Brennan until 17 March and the hearing is set for 16 March.
"I had decided at the beginning of this season that I would retire at the end of the current French championship," former Leinster player Brennan said in a statement.
"However, as a result of recent matters I've had to review that position.
"I had sought an adjournment of the ERC disciplinary hearing on the grounds that it interfered with my right to silence in other proceedings but this has been refused.
"I am therefore announcing my immediate retirement from rugby."