A smoldering cigarette or an electrical malfunction could be what sparked the massive Notre Dame Cathedral fire, Paris prosecutors said on Wednesday.

There’s no evidence the April 15 blaze that gutted the 850-year-old cathedral was deliberate, prosecutors said, following a two-month preliminary probe where investigators interviewed 100 witnesses and examined more than 1,200 clues.

“Several hypotheses have caught the attention of the investigators including that of a malfunction of the electrical system or that of a fire caused by a poorly extinguished cigarette,” said prosecutor Remy Heitz in a press release.

A newly opened judicial investigation will explore those theories and look into the possibility of negligence, Heitz said.

“If certain failings — which may explain the scale of the fire — have been brought to light, the investigations have not thus far been able to determine the causes of the fire,” Heitz said.

The 13th-century landmark was under renovation at the time of the inferno that toppled its iconic spire and burned through parts of the interior.

As the detective work continues, workers are busy cutting down 50,000 tubes of scaffolding put up for the pre-fire renovation. The tubes reached more than 1,472 degrees during the blaze, according to the Notre Dame Foundation.

French President Emmanuel Macron has pledged to resurrect the house of worship within five years.

Experts doubt that’ll happen, especially as many French billionaires who pledged funds to help with the renovation hadn’t pitched in a cent until recently.

On Wednesday the foundation announced that some of the donors, including Bernard Arnault, his family and luxury giant LVMH Group had paid 10 million euros, on a pledge 200 million.

Francois-Henri Pinault, chairman and CEO of Kering, the luxury group behind Gucci and other brands, also paid 10 million on a pledge of 100 million, it said.

With Post wires