The majority of French right-wingers believe that Notre Dame was set ablaze deliberately in a terrorist act. This sentiment is strengthened by the fact that Macron’s “state machine” has declared it an accident since day one. French conservatives are not convinced by official explanations about the tragedy. Right-wing French media says that Macron and the pro-Macron liberal media falsifies information about the fire to make it look like an accident and suppress the truth.
There continues to be no real explanation about how a building with one of the world’s most advanced fire alarm systems could burn out almost completely, while first responders found no fire and left the cathedral.
There is no evidence to support the claim that the "majority" of French conservatives or right-wing voters believe that the Notre Dame fire was started deliberately. There is no public data to support such a conclusion. However, pro-Kremlin and far right media in France and elsewhere exploited the tragedy to spread lies and conspiracy theories about the cause of the fire, including unfounded claims that it was a terrorist attack. More examples of this trend are available here.
Investigations into the cause of the fire are still ongoing, but all official sources are treating it as an accident, likely due to a short circuit in a temporary elevator used for renovation works. According to firefighters, the blaze began in the area under renovation. Zero links to terrorism or arson have been established.
Finally, there is no evidence to support the claim that first responders abandoned the scene - on the contrary, they are being honored for their bravery.