Tear gas has been used against football fans in Lille amid reports of renewed clashes at the Euro 2016 tournament.
It has not been made clear which team’s fans were involved. England fans have gathered in the city ahead of their match in nearby Lens against Wales.
Russian and Slovakian supporters are also in Lille, after their match at the city’s Stade Pierre-Mauroy.
The BBC’s James Reevell saw hundreds of England fans surrounded by riot police in the city’s main square.
The fans were then pushed back into the corner of the square by police in riot gear, he said.
By late afternoon, fans were back in the bars, the situation had calmed down and the police had “pulled back slightly”, he added.
England fan Oliver Larkworthy from Norwich is in Lille and was caught up in the tear gas, which was fired at the city’s railway station.
“I saw a massive crowd running down the street – English fans, Slovakian fans and locals mainly, a real mix,” he said.
“There is a massive mob of Russian fans standing outside the station just waiting to cause trouble. The whole thing is a disaster waiting to happen. It’s like a massive tinder box waiting to go off any minute.”
The Russian football team have already been given a suspended disqualification from the tournament following attacks by their supporters on England fans at their opening fixture in Marseille on Saturday.
Six England fans were jailed following Russia and England’s draw in Marseille on Saturday.
Michel Lalande, prefect of the Nord-Pas-de-Calais Picardy region, said a drinking ban was in place some parts of central Lille and the stadium.
Shops selling alcohol in the city closed from 18:00 local time (17:00 BST) on Tuesday and will reopen at 06:00 (05:00 BST) on Friday, he said.
However, the BBC’s Geraint Owen, in Lille, says small supermarkets were still selling alcohol on Wednesday afternoon, which is being drunk openly on the streets.
Vince Alm, of the Football Supporters’ Federation Cymru, said the ban was not enforceable. “There are so many outlets around it’s impossible,” he said.
England fans are being discouraged from travelling without a ticket, and the authorities are asking fans if they can wait to travel on Thursday to watch the Wales game.
Those without tickets can watch the match in the city’s fan zone, where lower strength beer will be sold.
Mr Lalande also said anyone carrying out violence would be removed from the country.
British Transport Police officers have been travelling with fans on Eurostar trains on Wednesday.
Eurostar is running some alcohol-free services, with no alcohol allowed through check-in or purchased at departure lounges or on board.