From his house on a hill in a southern suburb of Paris, Jean-Marie Le Pen likes to look at the city through an old brass telescope he keeps in his study. On recent evenings, the sky in the northeast has had an orange tint, and the leader of the far right National Front party has been able to make out distant pinpricks of burning buildings.

Each outbreak of rioting by black and north African youths puts more capital in his political bank, so this silver-haired veteran of French politics was in a jaunty mood as thousands of cars and dozens of businesses and schools were burnt in the worst outbreak of civil unrest France has experienced since the student protests of 1968.

“In the past 15 days,” said Le Pen on Thursday, “our party has acquired several thousand new members. We’ve received thousands of e-mails, faxes and letters from people who say, ‘At last we have understood. You were right, Monsieur Le Pen. They said you were an extremist, but you were a visionary. You predicted everything’.”

For decades, the bogeyman of French politics has been predicting that France will be submerged under an avalanche of Muslim immigration and lose its identity and freedom unless it fights back.

Has his hour come? As the banlieues burn, do the French, whose great-great-grandfathers conquered a vast empire on a “civilising mission” in the 19th century, really believe they are being destroyed by the bitter legacy of that imperium?

One of the many paradoxes in France’s attitude to its immigrants is that it has clung long and hard to its overseas realms. Le Pen cut his teeth as a paratrooper in the struggle to keep Algeria French. Abidjan, capital of the Ivory Coast and source of some of the rioters, was until recently the “Paris of Africa”, where shops famously stocked 15 types of camembert. A number of overseas possessions remain part of metropolitan France and send MPs to the national assembly.

Officially, France treats the children of the empire as fully fledged citizens. The reality, as has been brought home so painfully in the past two weeks, is that the cradle of human rights is a land divided.

The 10% of the population that is Muslim has been largely marginalised to out-of-town estates. Inflexible employment laws provide a featherbed for life for white citizens but leave the French-born children of immigrants on welfare. And, because official statistics are colour blind, the state has no measure of this disaster in its midst — until the Paris skyline is lit up with the glow of burning cars.

In 2002 Le Pen shocked the French left by beating the Socialist candidate in the first round of the presidential election. Holding their noses — “better a thief than a racist” — they kept out Le Pen by keeping Jacques Chirac in power. Chirac is now a feeble 72-year-old. His lieutenants, tasked with fighting the street fires, are more engaged in fighting each other for the succession. France is drifting. Will it turn to Le Pen for the solution? Or is there another way?

WHEN Stéphane Hérel was growing up in the northern Parisian suburb of Asnières-sur-Seine, he always wanted to be a policeman. Last week he got his chance. He enrolled in a “civil watch committee” to help restore order. Hérel, a municipal gardener who by day planted tulip bulbs in civic herbaceous borders, did not want to see his town destroyed at night.

Asnières was once a genteel riverside resort better known in the past for Georges Seurat’s famous painting Bathers at Asnières. Fantastically expensive Louis Vuitton suitcases are still made there in a 19th-century workshop-museum. It also, however, has a “problem district” — a high-rise estate that worries Manuel Aeschlimann, the town’s conservative mayor.

On Tuesday night, as hundreds of cars burnt across the country despite the declaration of a state of emergency, Aeschlimann provided Hérel and two dozen other volunteers, including an 82-year-old, with fire extinguishers and wished them good luck.

“We’re not Rambos,” he warned. “If you see anything suspicious, don’t intervene, just call the police.”