If invited round to a French person’s house for dinner it’s common to take a dessert with you, but turn up with a tarte aux fraises and you could be setting up quite the misunderstanding.

That’s because there’s an urban myth in France that offering a strawberry tart to a friend or neighbour indicates that you are in the market for a swingers evening (une soirée échangiste in French, just so you know what you’re signing up for).

No-one knows how this started and as with all urban myths (remember the one in the UK about the pampas grass and the swingers?) no-one has reported that it happened to them, always to a friend-of-a-friend, or perhaps someone’s cousin.

And according to French newspaper 20 Minutes, real swingers do not use this code.

As part of the paper’s ongoing series on Légends Sexuelles (the broad-minded among our readers can click here) their reporter spoke to several representatives of French swinging clubs, who said they had never used the term or heard it being used.