A blast has ripped through a street in Paris’s busy Latin Quarter, causing the facade of one building to collapse, blowing out windows and starting a huge blaze.

Thirty-seven people were injured, including seven who are in a critical condition, police said.

Witnesses said there had been a strong smell of gas moments before the blast.

One student described a “huge boom” followed by a “ball of fire” up to 30 metres high.

“And the building collapsed with a huge noise. I smelled gas, but took several minutes to come to my senses,” the student told the BBC.

Bar employee Khal Ilsey said he heard “a huge explosion…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.

A building partly collapsed in the explosion in the 5th arrondissement of Paris. Photo: Getty

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 ninth arrondissement.