PARIS — The pledges came in quick succession.

François-Henri Pinault, France’s second-richest man, put up an eye-popping 100 million euros to rebuild Notre-Dame, just as firefighters were dousing the last flames at the cathedral early Tuesday morning. Not to be outdone, Bernard Arnault, France’s wealthiest scion and a fierce rival to Mr. Pinault and to his father, François Pinault, upped the ante with a 200-million-euro gift a few hours later.

By Wednesday, the government had welcomed some 850 million euros — more than $960 million — offered in the patriotic name of salvaging the cultural treasure, as money from wealthy French families, French companies and international corporations poured in.

But the spectacle of billionaires trying to one-up one another quickly intensified resentments over inequality that have flared during the Yellow Vest movement, just as President Emmanuel Macron was looking to transform the calamity into a new era of national unity. There were accusations that the wildly rich were trying to wash their reputations during a time of national tragedy.

[A guide to The Times’s coverage, from the first moments to the investigation.]

“Can you imagine, 100 million, 200 million in one click!” said Philippe Martinez, the head of the militant CGT labor union. “It really shows the inequalities in this country.”