French police were out in force in the northern Paris suburb of Villiers-le-Bel to try to prevent a fourth night of unrest by youths. At least one car was burned by protesters. A significant police presence was deployed on Wednesday night (November 28) in Villiers-le-Bel, near Paris for the second consecutive night to avoid unrest and restore calm in the suburbs. Officials reported no major clashes between police and youths in the northern Paris suburbs, areas with mixed white, North African and African populations that suffer from poor housing, high unemployment and crime. Some 1,000 police were on the ground and helped restore calm despite, here and there, few cars burning. Earlier on Wednesday, moments after arriving back in France from China, President Nicolas Sarkozy sped off to a hospital in the Eaubonne suburb of Paris where a senior police officer, attacked at the start of the violence on Sunday, was being treated for serious injuries. Sarkozy, a law-and-order hardliner when he was interior minister during riots two years ago, praised the officer's courage and said nothing could justify such violence. He pledged to punish rioters who shot at police but sought to ease tensions with an independent probe into the deaths of two youths that triggered the unrest. The violence in the last few days has revived memories of the riots in 2005, the worst unrest in France in 40 years, when thousands of cars were torched after two teenagers were accidentally electrocuted in a power sub-station after apparently fleeing police. Police officials have said the latest unrest was nowhere near the scale of 2005 and was limited to a few areas, though the use of firearms so early in the disturbances has alarmed police. The new wave of violence erupted on Sunday (November 25) when two teenagers on a moped were killed in a crash with a police car.