Police investigating the Notre Dame fire are looking into why smoke detectors failed to go off, reports say.
The cathedral, which is currently undergoing construction work, went up in flames on Monday April 15.
French company Le Bras Frères, who are one of five firms working on Notre Dame, said alarms on the scaffolding surrounding the building’s spire did not sound.
Marc Eskenazi, head of communications at the company, told French newspaper The Connexion that detectors only went off inside the cathedral itself.
He added that the company were working alongside police with their inquiry.
Investigators have now been able to establish that the fire likely started at the centre of the cathedral’s roof, towards the base of the iconic spiral, CNN reported.
Officers are said to have reviewed numerous amateur videos and photos captured by those who first saw the smoke rising from the Paris landmark.Lena Dunham accidentally posted Jemima Kirke's number on Instagram
The network also reported that security guards told police they only noticed the flames for the firs time when they were ‘already three metres high’ at 6.43pm.
This could have been due to a smoke alarm failure, they said.
Firefighters were able to leave Notre Dame last night after architects and construction workers finished stabilising its damaged structure.
The promising development came as cathedral’s parishioners celebrated Good Friday in a nearby church.
They prayed for the damaged monument and celebrated its rescued relics, such as the Crown of Thorns, believed to have been worn by Jesus at his crucifixion.Manchester United star appears to confirm he's leaving club in emotional Instagram post
Lt. Col. Gabriel Plus, chief spokesman for the Paris fire service said: ‘There is no more risk the edifice’s walls could fall down’.
He added: ‘It’s a miracle that the cathedral is still standing, and that all the relics were saved.’
The cathedral’s rector has said a ‘computer glitch’ may have played a role in the rapidly spreading blaze that devastated the 850-year-old architectural masterpiece.
Rector Patrick Chauvet continued on that it might be ‘two or three months’ until we are able to know what happened for definite.