The flames and smoke plumed from the spire and roof of the gothic cathedral, visited by millions of people a year.
Just a day after the fire, more than 750-million euros (US$845 million) had been pledged, including 500 million from the three billionaire families that own France's giant luxury goods empires: Kering, LVMH and L'Oreal.
President Trump said Wednesday that he spoke to Pope Francis and offered his condolences and the assistance of USA expertise to help restore the landmark Notre Dame cathedral that was heavily damaged by fire.
The famed white marble sculpture of the Virgin Mary and Jesus have survived the fire at Paris' Notre Dame Cathedral, with photographs taken after the blaze showing the 1725 Pieta statue "Descent from the Cross" covered in ashes but still intact.
Macron's defiant comments indicated he wants the reconstruction of the cathedral to be completed by the time Paris hosts the Olympic Games in 2024.
There were also concerns for the towering mountain of scaffolding that had been erected prior to the blaze for fix work to the 90-metre (295-foot) spire, and that was subjected to intense heat, Plus said.
Bertrand de Feydeau, vice president of preservation group Fondation du Patrimoine, told France Info radio that the wooden roof that went up in flames was built with beams more than 800 years ago from primal forests.
"We still have the main parts of the building so hopefully we will celebrate again in this cathedral", Ambroise Laurent, the deputy secretary-general of the Conference of French Bishops, told CBC's Thomas Daigle.
French President Emmanuel Macron called the event a "terrible tragedy", and has already pledged a campaign to rebuild the cathedral.
In the aftermath of the Notre Dame fire, many have speculated that Unity's recreation of the church could prove instrumental in restoration efforts.
Aside from the structure, art experts were concerned about the fate of countless priceless artworks and artifacts inside.
Plus said that now the fire is out "this phase is for the experts" to plan how to consolidate the edifice.
"No one is talking about us", he said.
A tourist is looking for what she believes to be a dad and daughter whom she photographed sharing a heart-warming moment outside the Notre Dame Cathedral in Paris just before the historic landmark caught fire.
Renovation work on the steeple, where workers were replacing its lead covering, is widely suspected to have caused the inferno after the blaze broke out in an area under scaffolding.
View of the burning Notre Dame from along the River Seine.
Hidalgo said she will coordinate with Bishop Patrick Chauvet, the rector of Notre Dame Cathedral, to mobilize funds for a restoration, which said "will take several years".
A spokesman for the Paris prosecutor's office later clarified that it was church staff, not firefighters, who looked into the initial alarm.
"I think it's proof they can rebuild without the help of the game, but in the meantime it's there for people to explore", he said.
"In terms of security, I doubt we could have done more", Monsignor Chauvet said.