A blast has ripped through a street in the busy Latin Quarter of central Paris, causing the facade of one building to collapse, blowing out windows and starting a huge blaze.
At least 16 people were injured, including seven who are in a critical condition, police said.
The local deputy mayor Edouard Civel referred to a gas explosion in a Twitter post and witnesses told BFM TV there had been a strong smell of gas moments before the blast.
"I heard a huge explosion," bar employee Khal Ilsey said.
"And as I was leaving the restaurant, I saw flames at the end of Rue Saint-Jacques."
More than 200 firefighters were involved in the emergency response.
TV images showed firefighters manning hoses and aiming jets of water at the blaze while a plume of thick black smoke billowed into the sky.
The blast occurred in the Rue Saint-Jacques in the fifth arrondissement of central Paris.
The road leads from the Notre-Dame de Paris cathedral to the Sorbonne University and the Val de Grace military hospital and is a few blocks from the popular Jardin du Luxembourg.
The area is usually packed with tourists and foreign students in the early summer.
"I was at home writing... I thought it was a bomb," art historian Monique Mosser said, adding that many of the windows in her building had been blown out by the blast's shockwave.
In 2019, a gas leak caused an explosion which killed four people and injured 66 in the 9th arrondissement.