France's interior minister says that three people have been killed, including two firefighters, and 47 have been injured in a blast at a bakery that was apparently caused by a gas leak in central Paris.
Christophe Castaner told reporters at the scene "unfortunately the human toll is particularly serious".
He said 10 people are in critical condition and 37 others less seriously injured.
The blast and subsequent fire, caused by a gas leak at a bakery, destroyed several buildings in the historic 9th arrondissement, overturned cars and filled the streets with debris.
French journalists at the scene said the windows of buildings along the entire block on the Rue de Trevise in the commercial district were blown out at around 9am local time (9pm NZT).
Despite initial fears of a terror attack police quickly ruled the blast was caused by a gas leak in a patisserie.
Spanish Foreign Minister Josep Borrell confirmed a Spanish woman is among those killed.
"I deeply regret the death of three people after the explosion in central Paris, including a Spanish woman," he tweeted.
He shared condolences to her relatives and "wishes for a quick recovery to the other injured Spaniard."
El Pais reported the woman was a tourist staying in a hotel near the bakery.
Firefighters and police evacuated people from the damaged buildings and dozens of fire trucks raced to contain the blaze.
Several people were led down from upper floors on ladders pushed up on the outside of the building by firefighters.
Of the people injured, five received critical injuries others were seriously wounded, Paris' fire service said.
The blast rattled an already apprehensive city, which was on lockdown across the CBD due to the weekly violent protests by the gilet jaunes, or "yellow jackets'' who are seeking to unseat French President Emmanuel Macron.
The powerful blast scattered debris across several streets, with photographs showing twisted bicycles, mangled rubbish bins and building debris flung violently across the road.
Cars were upturned and on fire, and glass scattered across the streets and footpaths.
Witnesses described on French television the overwhelming sound of the blast and people trapped inside nearby buildings.
"There was broken glass everywhere, storefronts were blown out and windows were shattered up to the third and fourth floors," said 38-year-old David Bangura.
He said that as he approached the scene, a woman was crying for help from the first floor of a building: "Help us, help us, we have a child".
Emergency workers also treated some of the injured at the scene.
Silver-helmeted firefighters and red firetrucks filled the street and inspected adjoining courtyards.
A vehicle from gas company GRDF was stationed nearby.
The building is around the corner from the Folies-Bergere theatre and not far from the shopping district that includes the famed headquarters of Galeries Lafayette.
The bakery is on the corner of the streets Saint-Cecile and Rue de Trevise in central Paris.
"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.
"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.
Two helicopters landed on the nearby Place de l'Opera to evacuate victims.
Interior Minister Christophe Castaner said "the situation is under control" but warned the explosion had caused a "heavy toll."
"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.
Speaking from the scene, he said some 200 firefighters said were involved in the operation. An investigation was opened, according to the Paris prosecutor's office, which would not comment on what possible causes were being investigated.Prime Minister Edouard Philippe also arrived on the scene to survey the damage.
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.
- with AP