Steyn's appeal dismissed
The original ban was imposed for a dangerous tackle on Leinster counterpart Jonny Sexton in the European Champions Cup last month.
The 29-year-old – capped 53 times and one of the Springboks' stars of their 2007 World Cup triumph – was red-carded just before the half-hour mark of his team's colossal 3-57 defeat in Dublin, which ended their hopes of making the quarterfinals.
Steyn lodged an appeal on Tuesday, but this was rejected Wednesday by a three-man committee chaired by Scotland's Rod McKenzie.
"An appeal committee has decided to refuse an appeal by the Montpellier player, Francois Steyn, against the four-week suspension imposed on him by an disciplinary committee following his sending off during his club's European Champions Cup, Round Five match against Leinster," a statement said.
Steyn has so far been suspended for Montpellier's final Champions Cup pool match against Northampton and for the domestic French Top 14 match against Castres.
He will remain suspended for the Top 14 matches against Toulouse and Lyon, and will be free to play again on March 6.
