This BBC report talks about how the French government spent billions of francs over the years trying to improve the suburbs that are now cauldrons of unrest. But critics are now saying it was done really badly.
Some excerpts:
"If you do not accept that these policies have failed, what would it take to recognise failure?" sociologist Sebastian Roche said in an interview with the BBC News website.
The law and order situation in the suburbs, he says, is much worse than it was two decades ago - even when there is no rioting.
Neither has the economic plight of local youths improved: "We have the same inequalities as in the mid-1980s."
As Mr Roche sees it, one reason for the failure is that urban policies have focused too much on "urban regeneration".
In the late 1990s, for instance, the then Socialist-led government launched initiatives like 50 Great City Projects and 30 Urban Renewal Operations.
Since 2002, the centre-right government has continued with this approach, demolishing high-rise blocks with gusto and investing heavily in new buildings.
The bricks-and-mortar approach is all very well, Mr Roche says, but the underlying causes of the crisis, such as bad schools, have not seriously been dealt with.
Patronage
Another problem, he says, is that the money has been not been focused on the worst areas.
Instead, it has been spread too thinly and used for patronage purposes.
"What typically happens is that mayors of big cities go to the minister and ask: 'What about me?'" Mr Roche says. ...
Furthermore, the crisis of the suburbs may reflect structural problems in France rather than misguided action by any individual government.
Mr Roche points out that to improve education, you must allow local schools to choose their teachers and set higher wages.
But this is unthinkable in the country's heavily centralised education system.
France is also characterised by a high degree of social protection and many labour-market rigidities.
This helps those already in work but prevents the creation of low-skill, entry-level jobs.
The result is 25% unemployment among the young - and zero job prospects for the poorly-educated youths of the ghettos.
