By Henri Astier
BBC News Online
France is not the only Western country to insist on the separation of church and state - but it does so more militantly than any other.
Secularism is the closest thing the French have to a state religion. It underpinned the French Revolution and has been a basic tenet of the country's progressive thought since the 18th Century.
To this day, anything that smacks of official recognition of a religion - such as allowing Islamic headscarves in schools - is anathema to many French people.
Headscarves challenge French secular traditions
Even those who oppose a headscarf ban do so in the name of a more modern, flexible form of secularism.
This tradition can be seen as a by-product of French Catholicism, as progressives have always seen the pulpit as an enemy, rather than a platform, unlike in some Protestant countries.
French Enlightenment thinkers such Voltaire, Diderot and Montesquieu regarded religion as divisive, benighted and intolerant.
On the ropes
The French Revolution brought about a head-on clash between church and state.
Church assets were confiscated and priests made to swear allegiance to the republic.
Napoleon made peace with the Church
Both during the revolution and its imperial aftermath, the Vatican resisted the republican order Paris was trying to impose across Europe.
The French responded by marching on Rome twice - in 1798 and 1809 - and abducting recalcitrant Popes.
Napoleon Bonaparte reached a peace of sorts with the church, which was brought under state tutelage, but left alone as long as it confined itself to spiritual matters.
The arrangement, known as the Concordat, lasted a century. In 1905, amid renewed anti-clerical militancy, the Third Republic decreed the separation of church and state.
The law of separation meant strict official neutrality in religious affairs.
The French state could not allow any proselytising in public buildings - least of all schools, where the citizens of tomorrow were being taught.
The insistence on schools as religion-free zones goes to the heart of the French idea of citizenship.
The Republic has always recognised individuals, rather than groups: a French citizen owes allegiance to the nation, and has no officially sanctioned ethnic or religious identity.
Although it can be carried to extremes - such as colonial subjects being taught that their ancestors were Gauls - this view of citizenship is fundamentally non-discriminatory and inclusive.
School bans must be viewed in this context and are nothing new.
In 1937, the education minister of the day instructed head teachers to keep all religious signs out of their establishments.
This was not controversial - but then the state was confronted with a weak opponent in an overwhelmingly secular society.
In the 1960s and 1970s, mass immigration from former north African colonies brought a new challenge.
This did not lead to an immediate questioning of secularism. The first immigrants
had no desire to find in France the mullahs they had left behind.
1789: French Revolution
1789 & 1809: France marches on Rome
1905: Law on separation of church and state
1937: Schools instructed to keep religious signs out
1989: School ban on religious signs ruled illegal
1994: Ministers say schools can ban "ostentatious" signs
2004: MPs vote in support of ban on religious symbols in schools
Many of these older migrants are now shocked to see their children adopt conservative Islamic practices, and are at the forefront of moves to ban headscarves from schools.
But younger second or third-generation immigrants see things differently.
They have lived only in France, mostly in deprived areas. For many, militancy and headscarves are a way of expressing anger and forging an identity.
No one knows exactly how many French Muslims there are - the oft-quoted figure of five million is probably an exaggeration. But recent elections to their representative body suggest young, anti-secular and at times, radical Muslims speak much louder than older and more moderate community leaders.
Faced with this unprecedented challenge, the French establishment is divided.
Traditionalists argue that the Republic must uphold its secular principles as firmly as it did against divine-right monarchists in centuries past.
Headscarves in particular, it is argued, cannot be tolerated in schools, because they are instruments of propaganda for an intolerant version of Islam and symbols of the oppression of women.
The modernisers, on the other hand, say a ban would only strengthen the militants, and point out that the principles of secularism are not set in stone and can accommodate exceptions.
For instance, the eastern provinces of Alsace and Lorraine - which were German when the church was weaned off the state in 1905 - have kept the Concordat system which allows clergy to receive government salaries.
The legal status of the headscarf in schools remained unclear for many years, but a parliamentary vote in February 2004 finally decided the matter.
Backed by French President Jacques Chirac, ministers approved a law that will come into effect in September, banning all obvious religious symbols from schools - including headscarves, Christian crosses and Jewish skullcaps.
It is not yet clear whether this will achieve the aim of helping to unite the country or - as some have suggested - divide it more than ever.