The number 63 bus caught fire at around 9am on Rue des Ecles in the fifth arrondissement of the French capital, shortly after the driver had noted a problem.
He asked the passengers to exit the vehicle before the blaze took hold. No one was injured in the incident but the blaze caused major traffic disruption at rush hour.
Police cordoned off the area around Rues Monge, Rue des Ecoles and Rue Cardinal-Lemoine as a thick cloud of black smoke engulfed the area. Firefighters were called and the flames were under control by around 10am. Residents in nearby flats were told to leave their apartments.
"We heard two mini explosions," the mayor of the 5th arrondissement Florence Berthout told Le Parisien newspaper. "The driver showed an extraordinarily cool head. He managed to get thirty passengers off the bus in record time.
"As for the bus, there's nothing left but the metal shell. it's impressive," said the mayor.
But the mayor wants to know why a bus was able to catch alight and burn so quickly.
"There could have been tragic consequences," said the mayor. "I demand an investigation be opened."
Incendie quartier Jussieu à Paris pic.twitter.com/V6TknB2YK4— Kenneth Maussang (@KMaussang) January 16, 2018
Paris transport chiefs RATP confirmed that a probe would be opened and that the driver would be interviewed by police.