St Etienne are waiting to see what action the French Football League (LFP) will take after around 200 "ultra" fans burst into the stadium during Sunday's Ligue 1 game with Rennes, which was being played behind closed doors.
The fans got into the Stade Geoffroy-Guichard ground 17 minutes into the match, forcing referee Ruddy Buquet to temporarily stop play and send the teams back to the dressing room.
Only 18 people had been authorised by the LFP to attend the game, among them St Etienne president Roland Romeyer, who went to speak to the supporters who had broken in.
L'Equipe quoted him as saying: "I said to them: 'You're mad -- you're going to make us lose the game. Leave quickly. We're all fans of the club.'
"They replied: 'It's a message we wanted to send the League. We'll leave in five minutes.'
"I went to see the match delegate. And then they left as they had come, without violence."
Although the LFP's statutes do not cover an eventuality such as Sunday's, the body is still likely to sanction St Etienne.
The club had been ordered to play the match behind closed doors as a result of crowd problems during February's derby with Lyon.
"I hope it won't cost us," captain Loic Perrin said after the match, which finished 1-1 to leave St Etienne's hopes of qualifying for the Europa League in the balance.
"We just have to suffer what happens. It's already sad enough not to be able to play in front of our fans, who sing from start to finish.
"This matter mustn't penalise the players and the fans who weren't able to come today.
"I hope they'll be able to return for the next game."