Ulster Rugby has banned a spectator for life from the Kingspan Stadium following an investigation into verbal abuse aimed at Racing 92 winger Simon Zebo.
The former Munster and Ireland player tweeted after the Heineken Champions Cup game on 12 January: "I hope my ears deceived me with some comments directed my way from the crowd. #NotOn Django wins in the end."
'Django' would appear to be a reference to the 2012 Quentin Tarantino movie about an African-American slave.
Ulster said that they have written to Zebo and Racing 92 to apologise.
A statement sent to RTÉ Sport read: "Following a robust investigation into allegations of abuse directed at Simon Zebo during the fixture versus Racing 92 on Saturday 12th January, Ulster Rugby has sanctioned a lifetime ban on a spectator, for breaching our stadium regulations.
"We would like to thank the many supporters who provided information to assist our investigation.
"We are all very proud of our reputation as an inclusive club and the unacceptable behaviour of this one individual is not reflective of our supporters, or the values of our club.
"We have issued a written apology to Simon Zebo and Racing 92."