In his charming book A Small Treatise on the Great Virtues, the French philosopher André Comte-Sponville argues that politeness is overrated. It is not, he insists, a virtue at all - only its formalistic simulacrum. For instance, he says, the Nazis were often polite to their victims.

This surely gives a philosophical underpinning to a new survey of six western European countries that found French shop assistants to be among the least helpful, least knowledgable and most surly in Europe. The findings certainly accord with my experiences in the Galeries Lafayette on the Boulevard Haussmann, where staff have often been so eye-rollingly rude that they would have reduced me to tears, but for the fact I wouldn't give those nauseating cockerels the satisfaction, damn them!

By contrast, that nation of shopkeepers across the Channel is found by the survey to be the second most efficient and civil after those of Germany ... I was unable to complete that last sentence because I was put off by the tittering of readers who suspect good British service to be an oxymoron.

Can these findings really be true? After all, the Galeries Lafayette is not the whole of Paris, nor Paris all of France. Only in France has a waiter sidled up to me with a notepad and said the honeyed words: "Qu'est-ce qui vous fait plaisir, monsieur?" (What would give you pleasure, sir?) And only in France do shopkeepers ritually say to their customers, "Bonjour!" and "Au revoir! Et bonne soirée!"

Aristotle suggested that in order to become truly virtuous we need to act as though we are virtuous. Thus, if we act polite - with all the pleases and thank-yous that entails - we will become better, more civilised people. Now, the Nazis were not good Aristotelians. Quite possibly, many French shopkeepers are trying to be so. But some are clearly failing if this survey is true.

How could that happen? One possibility is that the large French public sector results in the lack of a "service ethic". But does that imply the British are less surly because of privatisation? This is an intolerable corollary.

In her book Talk to the Hand, Lynne Truss contrasts Gallic politesse with the Fawltyesque gracelessness of her native sales staff. My experiences leave me more conflicted. At a Marks & Spencer store the other day, I had to interrupt the following exchange between shelf-stackers with a pressing inquiry about pains au chocolat.

"So I told him to fucking fuck off."

"You fucking never?"

"Fucking did."

"Excuse me, is there an in-store bakery?"

"Just left at the wine, sir."

"Thanks!"

"No problem, sir. Have a nice day. And then he said ..."

This incident fits in with the view according to which, historically, the French have regarded us as foul-mouthed, while we have taken them as the height of refinement. Have we been right to do so? Perhaps the French have become surly because we can see through their attempts to be polite, and realise that behind their formal greetings lurk crypto-Nazi contempt and self-hatred.

Just a theory. It would be terribly impolite to suggest that it is true.