A powerful explosion destroyed a bakery in central Paris on Saturday morning, killing at least four people and injuring several others.
Two firefighters and two civilians succumbed to their injuries on Saturday afternoon, according to the Interior Ministry.
The blast blew out out dozens of nearby windows after a suspected gas leak, police and AFP journalists said.
Around 200 firefighters were mobilised to battle the fire that broke out after the blast and rescue residents in neighbouring buildings, Interior Minister Christophe Castaner told reporters at the scene.
Police closed off streets in front of Opera theatre as emergency services landed two helicopters in the street, apparently to evacuate victims.
"The toll appears to be high, and severe," Castaner said, adding that 100 police officers were blocking off several streets in the area, home to restaurants and tourist attractions like the Musee Grevin wax museum and the popular Rue des Martyrs.
The blast occurred shortly after 9am (0800 GMT), and was heard by residents and workers several blocks away.
"I was sleeping and woke up by the blast wave," Claire Sallavuard, who lives on the Rue de Trevise where the explosion occurred, told AFP.
"All the windows in the apartment exploded, doors were blown off their hinges, I had to walk on the door to leave the room, all the kids were panicking, they couldn't get out of their room," she said.
Rescuers eventually used a ladder to evacuate the family, who lived on the first floor.
Police sources said firefighters had already been responding to an alert of a gas leak at the site when the explosion occurred.
Cars were overturned by the blast and glass and rubble was strewn across large swathes of the street, as fire trucks and police continued to race toward the scene more than an hour later.
Prime Minister Edouard Philippe also arrived on the scene to survey the damage.
"There was an explosion in a bakery, it was accidental," Sylvain Maillard, deputy mayor of the 9th Arrondissement where the blast took place, told BFM television.
"There is heavy damage, lots of broken windows, and the bakery was totally gutted," he said.
Dozens of tourists, suitcases in hand, were evacuated from the many nearby hotels in the area, a popular weekend shopping destination for locals and visitors alike.
Other residents were in bathrobes or quickly dressing in the street as police helicopters circled overhead.
"We were sleeping when we heard the noise, it sounded like an earthquake," a teenager who lives on a nearby street told AFP.
The blast came with the city on edge ahead of expected protests by "yellow vest" anti-government demonstrations, which have often degenerated into violence and vandalism in Paris and other cities in recent weeks.
The central Place de la Concorde and surrounding areas were locked down by police barricades, as thousands of officers stood guard on the Champs-Elysees and other areas where protesters have clashed with security forces.