But what really matters is not religion as such, or even ethnicity. It is the future of France as a way of life and a culture. France used to be a very open and inclusive society, where most immigrants, whatever their background, tended to assimilate quickly and thoroughly into the mainstream culture and way of life. This is no longer the case with Muslims. According to a Fondapol 2014 survey, the proportion of “strictly religious” French Muslims rose from 27 per cent in 1994 to 42 per cent 20 years later. To quote again the Ipsos survey on Marseilles, 83 per cent of young Muslims described religion as “something important or very important”, against 40 per cent of non-Muslims (and 22 per cent of Catholics). Another Ifop survey last September suggests that 29 per cent of French Muslims see Sharia as more important than the law of the land, and that 65 per cent condone the Islamic rules of female “modesty” in the public sphere, including the hijab or burka and the burkini, the Edwardian-style all-body bathing suit.

What if such views and attitudes foster “no-go zones” or de facto enclaves in many parts of the country, or terrorism? Over the past four years, more than 2,000 French Muslims have joined Islamic State in Iraq and Syria. Conversely, about 200 people were killed and 300 were wounded or maimed in France by French-born jihadist attackers: from the murder of soldiers and Jewish teachers and kids in southern France in March 2012 to the massacre of cartoonists and Jewish shoppers in Paris in January 2015, and from the killing sprees in Paris in November 2015 and Nice in July 2016 to the murder of an elderly Catholic priest during Mass a few days later. President Hollande warned in his book of a looming “partition” of the country. The right-wing columnist Eric Zemmour, whose essay Le Suicide Français (The Suicide of France) sold more than 200,000 copies in 2014, prophesied a “coming civil war”. France’s most notable writer, Michel Houellebecq, sold 350,000 copies of Soumission (Submission), a 2015 novel about the election of a “moderate Islamist” as president of France in the 2020s, and an ensuing accelerated, albeit peaceful, Islamisation of French government and society.

While everybody agrees that immigration and Islam are major challenges, the mainstream parties have, on the whole, been unable to devise coherent answers. They contend that partition, civil war, or the replacement of the nation state by ethnic-religious communities (referred to as communautarisme) are absolute evils, and must be countered by a “restored” or “reconstructed” secular democracy. Many advise French Muslims to emulate the many compromises made by French Jews after 1789 — not realising that Jews were content to be “emancipated” and never entertained the slightest fantasies about converting the whole of Europe to their faith, whereas most Muslims understand full citizenship as the promise to be fully Muslim, and the right to propagate their own Muslim faith.

However, a growing minority thinks that secular democracy is not a practical answer any more and that the only way to resist an Islamic conquest is to restore a sense of community among the non-Muslim French, based either on the Christian tradition or the Enlightenment, or both. While Le Pen insists she is staunchly secular, she refers to France as an organic community. Among those Catholics who supported Fillon, many belong to a younger generation closer to conservative popes John Paul II and Benedict XVI — or even to the schismatic Archbishop Marcel Lefebvre — than to the Second Vatican Council fathers or their present heir, Pope Francis, and envisage the abolition or the revision of the 1905 Law of Separation of Church and State.