Two firefighters have died and nearly people 50 have been injured in a massive gas explosion that gutted the ground floor of a building in a central Paris shopping district.
The accident occurred as Paris was under security lockdown for a ninth consecutive Saturday of "yellow vest" protests, with large parts of the French capital blocked off by riot police.
Interior Minister Christophe Castaner said two firefighters died and 10 people had serious injuries, including one firefighter.
Another 37 people had lighter injuries, he said.
Earlier he had told reporters that two civilians had also died.
"As firemen were looking for a gas leak in the building, a dramatic explosion took place," Castaner said, adding that one of the firemen had been buried under debris for several hours.
Just hours after the blast, thousands of yellow vest protesters marched noisily but peacefully through the Grands Boulevards shopping district of northern Paris, just a few hundred metres from the scene of the explosion.
In recent years, France has suffered a string of deadly Islamist militant attacks in Paris, Nice, Marseille and elsewhere, but Paris prosecutor Remi Heitz ruled out foul play.
"A this stage we can say it (the gas blast) is clearly an accident," Heitz told reporters.
A police source said the explosion tore apart a bakery on the rue Trevise and witnesses said the force of the blast shattered nearby storefronts and rocked buildings hundreds of metres away.
More than 200 firefighters joined the rescue operation and two helicopters landed on the nearby Place de l'Opera to evacuate victims.
Ambulances struggled to access the blast area because of police barriers set up to contain any violence by yellow vest protesters.
An eyewitness at a hotel nearby said he saw flames envelop the ground floor of the building that was blown out by the blast.
"There was broken glass everywhere, storefronts were blown out and windows were shattered up to the third and fourth floors," 38-year-old David Bangura said.
He said that as he approached the scene, a woman was crying for help from the first floor of a building, saying, "help us, help us, we have a child".