The police are talking of “civil war”. The French Government said yesterday that it would not give in. Dominique de Villepin, the Prime Minister, declared that restoring public order was an absolute priority. But few expect any let-up in the rioting that has turned the suburbs of Paris into a battleground for the past week, as gangs smash shops, set fire to cars and hurl petrol bombs.

The Government has been wrong-footed in its response and the violence has yet to abate. The public has reacted with fear, anger and demands for a tougher police crackdown. The Right is calling for an end to the Islamicisation of France, which is home to more than five million Muslims. And France has been dramatically confronted with the failure of its controversial policies on ethnic and religious minorities.

The underlying causes are obvious enough. The poorer suburbs around Paris, as bleak as their names are picturesque, have become ghettos for ethnic minorities, many of them third-generation citizens with little connection to with their grandparents’ homelands. Jobs are scarce, drugs are rife and the young men grow up in a rootless subculture, prey to criminal gang culture or religious extremism. Women are confined to their homes, health and education standards are poor, and a community is alienated from the mainstream lives by the customs and rules prevailing in Algeria or Morocco. Emergency services, often the targets of stones as symbols of the State, do not enter the ghettos without police escort.

France’s tradition of an uncompromising insistence on “Frenchness” has made life difficult for minorities; though they have, in theory, the same rights and responsibilities as other citizens — a concept inherited from the colonial ideology of France’s “civilising mission” — in practice they suffer unofficial discrimination in jobs, housing and opportunities. Passions are easily inflamed, and most big towns suffer periodic outbursts of racial and religious violence.

Comparisons are misleadingly drawn with Britain. Paris has little of the tolerance and diversity of London and its tensions are more typical of the former mill towns of northern England, where minorities, even after three generations, live, learn and work apart from their white neighbours. Poverty exacerbates tensions and boosts extremism in both majority and immigrant communities.

The Paris riots have taken a toll not only on tolerance and social harmony but also on the French political establishment. Nicolas Sarkozy’s populist image as the tough, straight-talking Interior Minister ready to enforce the law has backfired, even though his policies have generally been more thoughtful than those of his predecessors. For a week President Chirac and M de Villepin have opportunistically exploited M Sarkozy’s troubles by standing back and refusing to intervene. Only now does the Government seem to realise that unless France sets aside politicking to take a hard look at root causes, today’s urban rioting could become violence on a much larger scale.