By Henri Astier
BBC News, Lyon
The riots that recently shook French suburbs highlighted the alienation felt by many youths of immigrant origin.
The Venissieux market near Lyon has a distinctly foreign feel
The violence, which lasted less than three weeks, was not regarded as a religious intifada. But the anger that fuelled it is also driving a rise of Muslim militancy in French ghettos.
Take Venissieux - a town that is only a short ride away from Lyon but feels like another country.
The Venissieux market could be mistaken for a Middle Eastern bazaar. Arabic is spoken everywhere. Stalls offer copies of the Koran. Men in white robes collect money for new mosques.
The town's foreign appearance has added to its rotten reputation. Taxis refuse to come here.
The overwhelming majority of residents are law-abiding citizens. But because of the radical few among them the place is widely seen as a den of Islamic extremism.
Abdelkader Bouziane, a fundamentalist imam recently expelled to Algeria, preached in Venissieux.
Two of the seven Frenchmen once held at the Guantanamo base also came from here.
Although France opposed the Iraq war, police are under no illusion that the country is immune from the worldwide jihad.
They say Venissieux and hundreds of similar immigrant suburbs around French cities are fertile ground for al-Qaeda.
"Muslim extremists have in recent years deeply penetrated the suburbs," says Stephane Berthomet, a former anti-terrorist investigator who now works for the Synergie police union.
France had an early wake-up call to the presence of jihadis on its soil.
In 1995 local Muslims helped carry out a wave of attacks that killed eight and injured hundreds in Paris. In 2000 police uncovered a bomb plot in Strasbourg during Christmas festivities.
The main recruiting cause at the time was Algeria's civil war, in which Paris sided with a repressive, anti-Islamist government.
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Many argue that nowadays radicals are able to tap into the alienation felt by many ghetto youths.
"They have no jobs, no future," says Farid Khelifi, a youth worker in Villeurbanne, another suburb of Lyon.
"They do not know who they are. They are told they are French but they are not given the same rights as the French. Necessarily some become radicals."
This views is shared by many - even among police.
"Immigrants have been parked in estates and excluded," says Mr Berthomet. "Youths can't see a way out of their condition and become the ideal recruits for radical preachers."
Writer Olivier Roy, author of Globalised Islam, says the main problem is not so much social deprivation as lack of a clear cultural identity.
"They have been uprooted," he says. "They are alienated from traditional Islam and their parents."
The young men who carried out the London bombings did not view themselves as members of the Pakistani community but as members of a radical Muslim Umma, Mr Roy notes.
French police frequently arrest suspected radicals in the suburbs
"The same is happening in France," he says.
No one knows exactly how many French Muslims have gone down the same route.
Yacine, a 17-year-old from Saint-Denis near Paris, reckons that five "out of more than 100 kids I know" have become radical.
This percentage seems in line with estimates from police, who believe that about 50 of France's 1,600 mosques or prayer halls are under the influence of extremists.
Of course, not all radicals are prepared to take up arms. Mr Roy says the number of jihadis in France could be around 1,000.
The numbers may be small, Mr Berthomet says, but they are rising.
"Youths who a while back would become criminals are now increasingly attracted to radical ideologies like Salafism," he says.
To deal with the danger, France has enacted tough anti-terror laws. Under the charge of "association related to a terrorist enterprise", anyone with the remotest link to a suspect can be placed under lengthy preventive detention.
Second largest religion
Five million Muslims (estimate)
1,600 places of worship
35% Algerian origin (estimate)
25% Moroccan origin (estimate)
10% Tunisian origin (estimate)
Concentrated in poor suburbs of Paris, Lille, Lyon, Marseille and other cities
France has also clamped down on radical speech. Agents keeps close tabs on mosques and groups gravitating around them. Imams who step out of line are expelled.
Venissieux preacher Abdelkader Bouziane fell foul of the authorities not for advocating violence, but for saying the Koran condoned the beating of unfaithful wives.
Does the zero-tolerance approach work? Police point out that it has attracted attention from countries, like Britain, who were slow in realising the domestic threat.
But many in the suburbs feel that all Muslims are being placed under suspicion.
"Mosques are not dens of terrorism," says Azzedine Gaci, who heads the regional Muslim council in Lyon. "Youths are not potential bin Ladens."
Staying on top?
According to Christophe Deloire, author of The Islamists are Already Here, the tough line can be self-defeating.
"When the government decides to expel an imam, many mainstream Muslims regard this as an attack on all Muslims," he says.
Olivier Roy argues that the government is wrong to regard the global jihad primarily as a religious phenomenon. Some disaffected youths, he says, are attracted to al-Qaeda simply because of its fighting image.
"In the 1970s they would have joined the radical Left. Today they join radical Islam, both because they often have Muslim roots and because it is the main violent ideology available."
If militants do not draw their force from Islam itself, putting Muslims under suspicion may not be the best strategy, Mr Roy argues.
French Police, however, feel they have no option but to continue monitoring the Islamic pool from which militants draw their recruits.
"In this field, either you are on top on things and then you barely manage to stop attacks, or you are not on top and then it is even harder to avert them," Mr Berthomet says.
Other features in Henri Astier's series on French Muslims: