A judicial investigation has been opened to identify and prosecute organisers of an underground party that drew at least 2,500 people in western France despite the country’s coronavirus curfew, the interior minister has said.

Gérald Darmanin tweeted that actions by police around the site at Lieuron in Brittany “led to the end of the illegal party without violence” on Saturday morning, 36 hours after it had begun.

He said more than 1,200 people had been fined for not respecting the curfew, not wearing a mask and taking part in an illegal gathering. .

Ravers from France and abroad converged on a hangar in Lieuron on Thursday night to party into the new year.

About 800 of the revellers were sanctioned for attending an illegal party, breaking curfew and not wearing masks, and the rest were mostly issued notices for using illegal drugs, Emmanuel Berthier, the head of the Ille-et-Vilaine prefecture, told reporters.

There were five arrests and sound and lighting equipment was also seized, he said.

The party took place despite France’s nationwide night-time curfew aimed at dissuading people from gathering during the pandemic.

The country has already had two national lockdowns since the outbreak started. The latest was eased in mid-December, but restaurants and bars are off limits and it is not clear when they might reopen.