“By wearing our glasses, you will become an ambassador of French spectacles around the world,” they wrote.

Mr Hollande, whose office pointed out that the lenses of his current glasses are in fact French and only the frames foreign, reportedly phoned the company no sooner had he read the letter and offered to buy another pair of their sunglasses for the summer on the spot.

A second French company then waded in, with Sabine Begault Vagner from Orleans sending him a “pretty pair of blue and red rectangular glasses”. The Elysée rang her too, saying the president would use them as his spares.

The “spectacle affair” emerged on the day that Arnaud Montebourg, France’s flamboyant economy minister was due to unveil his “roadmap for French economic recovery”, including a plan to create “tamper-proof” secret codes on tags for wine, foie gras and other local products to promote “le Made in France”.

Besides irking French spectacle makers, Mr Hollande’s change in glasses has triggered furious debate among political observers over their symbolism.

Jacques Séguéla, the advertising guru, said the new glasses were “final proof of his reformist coming of age”.

It is rumoured that the Danish Prime Minister recently had a glass of French red wine. There was no public uproar over that in Denmark.

But given this story it is hard not to think why France will not be the next euro zone country to get into (renewed) trouble…