The Marseillaise crackled tinnily but stirringly across the Parisian square; the banners, with their slogans expressing aggrieved patriotism, were held proudly upright in the blustery drizzle of a December afternoon. Young women, their faces framed by the controversial Muslim headscarf, took to the makeshift podium; the men hovered on the periphery, while bystanders watched democracy in action and French certainties in the dock. This demonstration was one of many before and since. President Chirac had just announced that a proposed law, banning signes religieux, such as the Muslim headscarf, from schools and other state-funded institutions, would shortly be debated in parliament. A commission headed by former education minister Bernard Stasi had completed its investigations, including the testimony of a small delegation of 'veiled' women.

This controversy is not new to France; girls wearing the foulard or hijab, aka le voile (veil), have been intermittently excluded from schools since 1989. This accords with France's adherence to the principle of separation of church and state, or laïcité, promulgated in 1905 and enshrined in the preamble to the Constitution of 1946. Laïc translates as 'lay', but in effect the term signifies an active secularism.

With 76 per cent of the population supporting them, the French parliament swiftly approved the law on 10 February; it will take effect in September. Though the law's remit includes the crucifix and the skullcap, it is the prohibition of the voile which has triggered the furore. To Khadija Marfouk, a young IT professional who came to France to study and work and who began wearing the hijab back home in Morocco in her late teens against her parents' wishes, this is "a new Dreyfus Affair".

France has Europe's largest Muslim population outside Turkey, roughly four million within a total population of 60 million, compared with Britain's 1.5 million. The French figure is a guesstimate; no statistics may be compiled on the basis of religious affiliation. French Muslims are mainly from the Maghreb (francophone north Africa), and, despite their numbers, are not so visible in public life as are their British co-religionists. That may change, when (or if) France's embryonic positive discrimination is allowed a successful gestation.

The debate about the hijab has largely consisted of non-Muslims sounding off about 'them' in the mainstream media, while Muslims fulminate among themselves. When Muslim women demonstrate, the press claim they have been forced to do so by their fathers and brothers. This was not the feeling I got from the demo I witnessed or from speaking with independent-minded, scarf-wearing Muslim women. Proponents of the ban allege that roughly 25 per cent of Muslim women wearing the scarf do so under duress. There have also been stories of non-compliant girls from strict Muslim homes being punished by rape.

French opposition to the veil is not necessarily fuelled by feminism; to some the scarf is seen as 'aggressive', an added irritation to proselytising and the disruption of the school syllabus when it diverges from Muslim belief. One commentator has pointed out that the hijab signals a woman's unavailability as a partner to non-Muslims, thereby hindering miscegenation, and hence social cohesion. The anti-racist organisation, SOS Racisme, is not overly sympathetic to the veil-wearers.

In their book La République et l'islam, Jeanne-Hélène Kaltenbach and Michèle Tribalat subordinate individual rights to 'the common good'. The authors explain that a school "is not an ordinary public amenity, but rather an 'organ of the State' whose objective is to emancipate its pupils in order to make of them citizens endowed with freedom of conscience. Thus the school requires total neutrality." The authors add: "The student is much more than a simple user [of the school]. There cannot be one laïcité for students and another for their teachers."

British readers might jib at this somewhat preachy tone, but it serves as a timely corrective to our diminishing civic sense, and a reminder that our two nations have much to learn from our differences. Still, delicate and well-nigh intractable problems do arise when a nation's loss of homogeneity reaches critical mass. In France, as in the UK, there are cultural differences in the areas of parental discipline, sexual segregation and diet. Immigrants from the Maghreb are implicated in verbal and physical attacks on France's Jewish community. So the anti-veil campaign could be read as a coded message to France's ethnic minority and to the world at large, that some tenets of nationhood are not negotiable.

This really is a very French affair. For example: that the December demonstration was held in the Place de la République, and indeed that that shabby square is dignified by so resonant a name, is a peculiarly French irony. La République, la laïcité and, to a lesser extent, la constitution, were repeatedly invoked by callers favouring the ban, on a Radio France phone-in last November. In his New Year's Eve message to the nation, Chirac promised them not only sorely-needed training and jobs, but also a laïcité that is "open and generous, and that will bring harmony..."

Clearly then, the French Revolution and the subsequent upheavals cast long shadows: while the British are relatively passive subjects, the French are active citoyennes et citoyens, with responsibilities as well as rights. Add to the equation an intense dislike for the Catholic clergy, rekindled during the Vichy regime, when the church once again enjoyed prosperity and oppressive power, and you have what one taxi-driver robustly dismissed as a tapage (hullabaloo). He was not alone: a recent poll found that 88 per cent of teachers objected to the amount of media attention given to the question.

Hullabaloos can be diversionary. This one, by dominating news bulletins and decimating rainforests over the past months, has provided the ruling UMP with a welcome distraction from France's social and economic woes. Also, with regional elections due in March, it may entice prospective Front National voters to the UMP, while burnishing the party's feminist credentials.

A direct appeal was made to Chirac in the form of a petition in a December issue of the weekly magazine Elle, signed by both men and women, Muslim and non-Muslim, and accorded a prominent position, with a follow-up in the next issue. One of the signatories, the president of the campaign group 'Ni putes ni soumises' (neither prostitutes nor submissives), Fadela Amara wrote: "In the name of my close attachment to secularism, I say 'yes' to freedom of conscience, but 'no' when that freedom deals a death-blow to sexual equality, the fruit of a long, hard struggle." French women only won the vote in 1945, so that struggle, and the life of Simone de Beauvoir, fall within living memory. Such fervour would be unimaginable in a British glossy, catering, as they appear to do, for vacuous Bridget Jones clones. Suddenly it seems downright churlish to mock the French.

And yet... "Is that all 'liberty' means, just not wearing a scarf?" Marfouk asked - and to me, at any rate, the question is unanswerable.

Incensed by the wholesale demonising of the way of life of ethnic minorities that underlies some of the pro-ban discourse, Marfouk points to the large numbers of non-Muslim women who are victims of domestic violence.

'Ni putes ni soumises' campaigns on issues around violence towards women, pointing out that banning the veil alone will not improve women's lot. Such comments are welcome in a debate that has become blinkered. A quarter-century of combating the irrational phalanxes of the Taliban and the mullahs has, I fear, blunted feminism. The Elle petition claims that any laxity on the issue of the veil "would be seen by every woman in France as attacking her liberty and dignity." One could - a generation ago one did - say the same about degrading images of women in ads and films, about the insidious sexism that pervades western culture. This might be an opportune moment to revisit those concerns, and take some of the heat off Islam.

Just as there are Muslim women who support the ban, so many non-Muslims oppose it. The eminent thinker Christine Delphy, for example, points out that the veil has different meanings in different circumstances, and is not per se a symbol of subjugation. In Le Monde in February, four former members of the Stasi panel denounced the Commission for, among other things, losing sight of its aim, and advocating a secularism that defined itself purely by prohibitions.

Another contributor proposed that, rather than stigmatising young Muslim women, France should address the fact that many imams do not speak French. In a cogent, wide-ranging article, philosophy lecturer and educationalist Bruno Mattéi urged his readers to focus on the ever-widening divisions in French society, on the level of racism, social exclusion and deprivation, with their corollary, increasing under-achievement, particularly among children of immigrant families.

School exclusions for flouting the new law will only exacerbate the problem. While rigid in some ways, France's laïcité can be conveniently flexible. Since 1959, France has allowed élite Catholic schools to be set up, which are under contract to, and funded by, the state. "We don't have laïcité, we have catho-laïcité," comments Marfouk. Already these Catholic schools, which have an open admissions policy, have become a refuge for Muslim girls barred from non-denominational schools for wearing the scarf.

There are also three private Muslim schools in French territory, of which only one is under contract to the state. The other two are not yet eligible to apply (they would need to have been open for five years and to follow the national curriculum). Meanwhile, they are self-funding, and no doubt those funds will stretch to establish more such schools.

Marfouk does not welcome such segregation, while one of the Elle petitioners, writer Elisabeth Roudinesco states: "As for young Muslim women who wear the veil of their own free will, they are agitating for a conservative revolution, and a faith school would seem to me to be better adapted to their needs."

Thanks to this law and these attitudes, France looks set to become a more fragmented society - but as the French saying goes: 'rather than take a step backwards, people would commit suicide.'

Vera Lustig is freelance journalist who travels frequently in Europe