Saint-Étienne, one of France's biggest clubs, were relegated from Ligue 1 on Sunday after losing a penalty shoot-out in their play-off against Auxerre, who return to the top flight after 10 years away.
Their defeat was greeted by a pitch invasion by angry Saint-Étienne fans and the intervention of French police who used tear gas to stem the trouble.
Saint-Étienne, who finished third from bottom in Ligue 1, had already drawn the first leg of their play-off 1-1 with Ligue 2's Auxerre.
Sunday's second leg at their Stade Geoffroy-Guichard also ended 1-1 with Saint-Étienne's Mahdi Camara cancelling out Hamza Sakhi's opener.
With the scores 2-2, the tie went into a penalty shoot-out which Auxerre edged 5-4 with goalkeeper Donovan Léon making a crucial save to deny Ryad Boudebou.
As soon as Birama Touré converted the final penalty to win the tie, Saint-Étienne fans invaded the pitch and threw flares towards the official stand.
The players of both teams took refuge in the changing rooms but Prime Video television footage from the tunnel showed players, stewards and staff coughing from tear gas used by the police on the pitch to disperse the invaders.
Saint-Étienne have already been sanctioned several times this season for the behaviour of its supporters and this game was played with one stand closed following incidents during the match against Monaco at the end of April.
The result marks the end of a nightmarish season for the 10-time French champions who are now facing serious financial difficulties as they return to Ligue 2 for the first time since gaining promotion in 2004.
Sports ministry hosts meeting over Stade de France chaos
France's sports ministry on Monday will host a meeting of security and football officials following the chaos that marred the Champions League final between Liverpool and Real Madrid, as Paris prepares to host the 2024 Summer Olympics.
Sports Minister Amélie Oudéa-Castéra, who will chair the meeting, said they want to identify what went wrong to avoid a repeat of Saturday's scenes outside the Stade de France near Paris.
The Liverpool club said it has called for an investigation into the treatment of its supporters ahead of the game, when thousands of ticket holders struggled to enter the stadium.
Police used tear gas and pepper spray on fans outside, while others managed to scale fences to access the stadium.
>> Chaos at Stade de France mars Champions League final
The scenes tarnished the image of the French capital, raising questions about its ability to host sporting events as it gears up for the 2024 sporting showpiece, as well as the 2023 Rugby World Cup.
Oudéa-Castéra expressed regret that "some supporters who had tickets were not able to access the match".
Monday's meeting at the sports ministry, due to start at 11am Paris time (0900 GMT), will involve European football governing body UEFA, French football chiefs and the French police.
Interior Minister Gérald Darmanin and Paris police chief Didier Lallement will be in attendance.
"The priority now is to identify very precisely what went wrong ... in order to learn all the lessons so that such incidents do not happen again at our future major international sporting events," said Oudéa-Castéra.
(FRANCE 24 with AFP)
