Philip Burger, the South African fullback and now of Perpignan in France, has been suspended for 30 days.
Burger was shown a red card by the referee Jean-Pierre Matheu when at the end of the match against Montpellier Burger verbally abused the referee.
Former Cheetahs star Burger has not played since that match and will be eligible to play again on September 22, 2009.
The decision follows a disciplinary hearing by the Ligue Nationale de Rugby, the body which regulates professional rugby in France.
Perpignan, the reigning French champions - who lost 18-12 to Montpellier on August 22 - have resolved not to appeal against the sentence.