[BenLurkin]

“A short-circuit might have caused the fire. Some suggested causes of the fire include a short-circuit from the spire’s electric bells, or an elevator, or cigarette butts left by workers.”

https://en.wikipedia.org/wiki/Notre-Dame_de_Paris_fire#Investigation

My money is on a “Center Fuel Tank Explosion”

[yesthatjallen]

Time-lapse images taken by a camera installed by them showed smoke first rising from the base of the spire.

Here's my issue.

The fire department was alerted by an alarm. When they arrived they searched the building and apparently found neither a fire or smoke. They left only to return later to a raging fire.

WHAT DID THEY MISS? How complete was the search that they didn't find smoldering, a fire, or smoke?

Either they were sloppy in their search or someone was in the building when they left and started the fire.