To burkini, or not to burkini? This is the question that divides France in the run-up to the first round of voting on 12 June for the next National Assembly. The pre-election political conversation here had been pretty stale and entirely predictable. Enter the burkini. The political and media class is presently talking of nothing else. Not since Brigitte Bardot took her top off in God Created Woman has the nation obsessed so compulsively with appropriate female swimwear.

Designed originally for Australian lifeguards uncomfortable with traditional swimwear, the burkini has not gone down well since arriving in France five years ago. Something about the garment seems to drive the French to distraction. The burkini has been widely banned by mayors of the left and right. On the Côte d’Azur, municipal police garbed head to toe in black patrol gear were deployed to beaches to order Muslim women to uncover themselves.

The burkini row has found new life thanks to an election season in which nobody seems to have much to say. Grenoble has been the flashpoint. On Monday the Green party mayor, Éric Piolle, to a tempest of political and media attention that continues unabated, lifted the interdiction on the burkini at the municipal lido. He then told women they can wear what they like and even bathe topless if they wish. Surreally, this has now become a national issue.

The row triggered not just Marine Le Pen and Éric Zemmour, who predictably regard the burkini as an affront to republican values, but President Macron’s interior minister, Gérald Darmanin, who this week demanded that the departmental prefect intervene to reimpose the Grenoble ban.

It has also mobilised the camp of the left, led by Jean-Luc Mélenchon, with whom Mayor Piolle is allied. The Mélenchon alliance including the socialists, communists and his own Insoumis, has positioned itself as Islamic-friendly and counts on big votes from the suburbs where Muslims live as it attempts to establish itself as an influential opposition in the Assembly.

France is a country that has always maintained rules about swimwear in public pools, even though on many beaches, toplessness is ordinary and bottomlessness fails to startle. At the pool or lido, women and men are typically required to wear form-hugging costumes, supposedly in the interest of hygiene. For men, Speedo-type swimsuits are obligatory; surfboard trunks will have life guards blowing whistles. Except in Grenoble, where even these have now been permitted.

There’s an argument mostly unheard here that the burkini is actually a liberating garment for many women who have been unable previously to swim. French Muslim women can be seen wearing hijab on some Mediterranean beaches but they usually remain fully dressed and rarely enter the water.

France is oddly fertile territory for ferocious rows about what Muslim women should or should not wear. We’ve experienced these storms before over veils (banned), headscarves (tolerated, mostly) and burqas (horror of horrors).

The sensitivity is partly explained by the French idea of laïcité, the separation of state and religion. Veils are forbidden in schools – as are crucifixes. But there’s more to it. Even though the burkini is not a traditional garment, it is regarded by many, including in the mainstream, as a provocation. It provokes a certain rage. On the eve of an election, the burkini has become the symbol of the unbridgeable divide between les français de souche and those whose origin is elsewhere.

A recent poll says 69 per cent of voters are opposed to the burkini, including a majority of left-wing voters. Still, it’s unlikely the garment will decisively sway the electorate in the forthcoming elections. It’s simply an opportunity for the politicians to cater to their bases and for the world to laugh once again at French exceptionalism.