During a Toulouse v Ulster match at the Stade Ernest Wallon on 21 January 2007, Brennan jumped into a section of the crowd housing Ulster supporters and struck a male spectator. Brennan alleged afterwards that abuse towards his apparent "watered-down pints" in his Toulouse bar triggered his action. His uncle took this further alleging sectarian abuse had taken place, a claim initially supported by the club before swiftly being retracted. In their investigation of the incident European Rugby found no such abuse took place. They found that Brennan was being baited over the standard of the bar he co-owns in Toulouse.