Charlie Hebdo attack: The suburbs and the suspects
The literal meaning of the word is suburb. But "banlieue" means a great deal more in the political lexicon of contemporary France. For many French, it has become synonymous with the country's bitter debates over immigration and the place of Islam in public life.
In France public opinion is outraged in the wake of the Charlie Hebdo attacks. But it is not polarised between Muslims and the rest of society. At least, not yet.
The political and religious mainstream has been quick to make the distinction between Muslims as a group and the more radical adherents of the faith.
But there is a real fear that the violence could intensify suspicion between communities. For Eric Bade, who lives in the northern Parisian banlieue of Gennevilliers, a friendly neighbour turned out to be a terrorist.
He lived next door to Cherif Kouachi, one of the suspects in the Charlie Hebdo attack. Mr Bade remembers Kouachi as a quiet individual - devout and living a simple existence. He last saw him three days ago.
"He was nice, courteous and clean and very helpful with disabled people. I saw him here every day," he said. "You could never imagine he would do something like that."
Just one hundred yards down the street in a Muslim-owned bakery a woman told me that she now lived in fear. "These people came from here, of course I am afraid," she said.
For her the attack threatened her family's place in France. "Because we have children we are afraid of everything. Everybody is looking at us as if we did it. Everybody says you are Arab, you are Muslim."
While there have been isolated attacks on Muslim-owned properties, most French people are heeding the appeal for national unity.
At the Grand Mosque of Paris there was an unprecedented show of interfaith solidarity as Buddhist, Jewish and Christian leaders joined Muslims in the minute's silence for the dead.
When I asked Francois Clavairoly, spokesman for the Protestant churches of France, if more people now feared Islam he was adamant in his response.
"We are here to say that Islam has its own full place in the Republic and we say this together in unanimity."
But for all the officially inspired appeals to unity, and a genuine desire on the part of citizens to come together, the government is now under huge pressure to confront radical Islam.
Religious leaders like Abdelrrahmane Dahmane, from the National Council of Democratic Muslims, says the key to tackling the problem is destroying the appeal of fundamentalist Islam among the alienated young.
"We need to be very careful with such young people. They are nurtured by fundamentalists who are members of terrorist groups. These people who learned the values of the democracy and the republic in our schools should not commit these kinds of crimes."
Despite major investment by the state after riots a decade ago the banlieues remains a focal point of alienation among younger Muslims.
Unemployment is about 40% among 15-to-24 year olds in many estates - four times the national average. But of course, alienation is about more than economic crisis.
Perhaps the greatest challenge facing the state is not that of security, but rather one of identity. It is to convince young men who do not feel part of French society, who are drawn by the chauvinistic appeal of fundamentalist ideology, that they owe allegiance to the republic.