The ‘broadest shoulders’ in France will have to bear the heavier burden too. 

Sir Keir Starmer warned Britons just over a month ago that wealthier people would have to pay more tax, though he didn’t on that occasion explain why pensioners would be clobbered as well.

Now the new French Prime Minister, Michel Barnier, best known to Britons as the chief negotiator for Europe over the Brexit deal, has confirmed rumours of higher taxes in France.

For wealthy French families – those with an annual income of more than €500,000 (£420,000) – there will be a temporary income tax rise. 

Temporary is supposed to be one or two years. The estimated additional revenue has been put at €2billion, so not that much additional money.

There will also be a rise in corporation tax for companies with more than €1billion in turnover, which will apparently affect about 300 enterprises, as well as other smaller additional changes.

Interestingly, French pensioners are being hit too. They will start to get their agreed annual rise in rates next July, instead of on January 1 as usual, thereby saving the state six months’ of the higher payment.

Details will be announced this week, but from what we know so far, it rather looks as though Barnier is failing to observe the renowned rule of taxation, attributed to Jean-Baptiste Colbert, controller-general of finances for Louis XIV: ‘The art of taxation consists in so plucking the goose as to obtain the largest possible amount of feathers with the smallest possible amount of hissing.’ 

But there will be a lot of ­hissing for not many feathers. So why do it?

The answer is that France’s fiscal position is in much more of a mess than ours. 

Their budget deficit for the current year could be as high as 6 per cent of GDP, whereas ours is a bit above 4 per cent. Total public debt is 111 per cent of GDP, against 100 per cent for the UK.

Taxes are already the highest in the developed world, though that hasn’t stopped wealthy French people becoming extremely rich. 

Bernard Arnault, head of the ­luxury conglomerate LVMH, is number four in the Bloomberg Billionaires’ Index, with a net worth of $193billion. 

Indeed there are six French people in the top 100, whereas there are no Britons at all. (The richest Brit, Sir James Dyson, with $20.5 billion, comes in at 105).

The markets naturally are well aware of the precarious position of French national finances and have started to charge the country more for its debt. 

The probable trigger for Barnier’s action was the yield on 10-year French government debt rising above that of Spain, and at one stage reaching nearly as high as that of Greece.

On Friday, the rate for France was a whisker below 3 per cent, which while much lower than the UK at 4 per cent, was still a little higher than Spain and much higher than Italy. What does this mean for us here?

I can see three messages. One is that the idea of a temporary tax is a seductive one. You get some revenue and if people really believe that it will be a one-off, they will not take radical measures – such as moving abroad – to avoid it. 

It would not solve any longer-term problems, but I can see some clever clogs in the Treasury putting it forward to Chancellor Rachel Reeves as an idea for us to emulate.

A second is that the cost of servicing the national debt will become a real constraint, not just on her but on future chancellors for the foreseeable future.

It will be more like the 1950s, when the huge debt burden from the Second World War hung over every fiscal decision. 

The Government had to chip away at the debt, holding down the cost of servicing it and trying to get the big number down.

And third, Western democracies are at the limits of taxation. That limit varies from country to country. It is perfectly reason­able that if citizens want to pay more tax for what they feel will be better public services, they should do so. 

But France has hit the buffers – saying the increase will be temporary acknowledges that. I suspect we are close to hitting the buffers too.