The scaffolding company that worked on the roof of the Notre Dame Cathedral in Paris has said its workers smoked on the scaffolding, but ruled out that a cigarette butt started the fire.

According to a news report by Paris Reuters, a spokesman from family-owned Le Bras Freres told the news organisation that some workers of its Europe Echafaudage scaffolding unit had informed the police that they had “sometimes” smoked on the scaffolding, despite a smoking ban on the site.

“We condemn it. But the fire started inside the building… so for company Le Bras this is not a hypothesis, it was not a cigarette butt that set Notre-Dame de Paris on fire,” Le Bras Freres spokesman Marc Eskenazi said.

French newspaper The Canard Enchaine reported that police had found the remains of seven cigarette butts in the burnt-out remains of the cathedral.

Eskenazi said it was impossible to set a log on fire with a cigarette butt and questioned how cigarette butts could have been found on the site.

“If cigarette butts have survived the inferno, I do not know what material they were made of,” he said.

French officials have said that it is not ruling out any theories about the cause of the fire and investigations are continuing.