Since the Notre-Dame fire, we've seen how deep billionaire's pockets are. For the right cause.

The Notre-Dame cathedral fire stunned onlookers into silence on Monday afternoon, as the heart of an icon that had stood for more than eight centuries was reduced to ash in a matter of hours.

There were no deaths, no serious injuries, but it was a tragedy for Parisians, nonetheless. As well as being a drawcard for millions of tourists each year, Notre-Dame – which translates to ‘Our Lady’ – is considered the spiritual heart of the city. To them, it is a ‘she’, a symbol of the city’s endurance.

Yet as firefighters reduced the ferocious blaze to embers, few could have predicted just how much some super-wealthy Frenchmen were intent on continuing that legacy, on seeing their lady stand tall again.

Billionaire businessman Francois-Henri Pinault (pictured above), founder of Gucci parent company, Kering, pledged 100 million Euro towards a Notre-Dame restoration fund announced by President Emmanuel Macron. Hours later his ‘nemesis’, CEO of luxury brand group LMVH, Bernard Arnault, pledged 200 million.

L’Oreal’s primary shareholder, the Bettencourt Meyers family, also declared they would donate 200 million Euro to the cause. And Patrick Poyanne, boss of French oil company Total, promised 113 million.

Doing the maths? Yep, that's 613 million Euros (roughly AU$964 million) from just four french families.

Donations in the tens of millions also came rolling in via various corporates: advertising, industrial companies, banks, private equity firms, etc. And combined, all put France well on its way toward racking up the estimated 1 billion Euros needed to reconstruct the Gothic masterpiece.

But it's the staggering donations from those four magnates that are raising eyebrows.

They're generous, sure. But given the speed and depth at which they were prepared to plunge into their pockets, it's difficult not to think about what else may deserve a slice of their eye-watering wealth. After all, there are causes much larger, much more pressing than this. Causes for which human lives are at stake.

The water/power crisis in Venezuela, perhaps. Families starving due to the war in Yemen. The communities affected by Cyclone Idai in Mozambique last month - a storm that left more than 600 dead, 1600 injured and 100,000 displaced.

It's a sentiment echoed by historian Mark Stuchbery via Huffington Post: "It’s important for some to remember that such a wonderful edifice was built to celebrate a faith that emphasises giving aid and comfort to the poor."

French politician and trade unionist, Philippe Poutou, took it a step further on Twitter, calling the top-tier donations "a contest of tax evaders"; a nod to the fact that French corporations are eligible for a 60 per cent rebate on cultural donations, picked up by taxpayers. (Pinault has declared he won't accept any deduction on his donation.)

It's also become fuel for France's Yellow Vest campaigners, a collective of thousands of demonstrators who jammed Paris' streets in November to protest high cost of living and economic inequality in the country. What demonstrates their argument more clearly than an individual mobilising 200 million Euros with a few clicks?

“If they’re able to give dozens of millions to rebuild Notre Dame,” CGT labor union boss, Philippe Martinez, told The New York Times, “they should stop telling us that there is no money to pay for social inequalities.”

But it's a sentiment tweeted by American author (and Catholic) Kristan Higgins that perhaps captures it best: "Donate to help Puerto Rico recover. Donate to get the people of Flint clean water. Donate to get kids out of cages. Jesus didn't care about stained glass. He cared about humans."