The French Football League (LFP) have provisionally banned Montpellier fans from travelling to away games and closed two stands at their Stade de la Mosson stadium after Sunday's trouble-marred 3-0 victory over Nimes.
The game -- the first derby between the teams in 25 years -- was held up for nine minutes when the surge caused by Ambroise Oyongo's 28th-minute opening goal resulted in a barrier collapsing.
Montpellier's third and final strike -- from Gaetan Laborde on 78 minutes -- led to an interruption in play of nearly 30 minutes as police, club officials and players tried to calm the situation before the match was played to a finish.
Following an emergency meeting of its Disciplinary Commission on Monday lunchtime, the LFP announced in a statement it had taken swift action, and said it will be investigating the incidents further, suggesting further punishments could be handed down.
A statement read: "Given the seriousness of the matter, the Disciplinary Commission has decided to open an investigation into the matter and provisionally close the away sector for Montpellier fans travelling to games, to close the lower section of the Etang de Thau stand and the upper section of the Petite Camargue stand."
Tensions were expected to be high following the alleged theft this summer of an historic Montpellier banner by Nimes ultras, known as "La Butte Paillade."
Following Montpellier's third goal, Nimes supporters unfurled a banner declaring that "The Devil no longer dresses la Paillade" in reference to the devil's head that had been cut from the banner and smuggled into the stadium in sections.
Having been pieced back together, it was then brandished by the travelling fans after their team had gone 3-0 down, provoking the ire of Montpellier supporters, who had to be held back by riot police causing the lengthy delay.
"Things started to heat up in our stand, several guys close to the leader wanted to go onto the pitch," Remi, a Montpellier ultra, is quoted as saying by France Football.
"The riot police came to stop them and started aiming a rubber bullet at the stand. Finally, the riot police tear-gassed the stand. People had to take cover outside, families with children had to leave the stand."
Montpellier president Laurent Nicollin insisted that the players' safety had never been in jeopardy because there had been no pitch invasion.
"I went to see the fans to try to calm them down, we were winning 3-0, victory was assured. The only thing I want to highlight is that there was no pitch invasion, no player in danger," Nicollin said. "The club's security forces stopped them. There was a good show on the pitch, it was a bit mad in the stands, but that's the south."