Police fired tear gas at rioters hurling stones and torching cars, firefighters said Friday, in a third night of unrest in a central French town of Firminy over the death of a local inmate.

The rioters threw projectiles at police and firefighters and trashed police cars in the overnight clashes in Firminy, outside the city of Saint-Etienne, according to the regional fire department.

Police responded with tear gas.

No injuries were reported. Police say six young people were detained. The fire department says 10 cars and seven stores in a shopping centre were torched.

The unrest began after 21-year-old Mohamed Benmouna was hospitalized in a coma Tuesday after police said he tried to hang himself in his jail cell. Benmouna, accused of attempted extortion, died the following day.

Peers in his working-class neighbourhood suspect that Benmouna died at the hands of police, and his parents filed a judicial complaint asking for a full investigation into what happened.

Dozens of youths went on a rampage Tuesday night, burning 30 cars and hurling stones at police in three neighbourhoods nearby. Police reinforced controls on those areas, and the next night was calmer, though a few cars were still set ablaze.

Tensions reignited Thursday night, after prosecutor Jacques Pin said preliminary medical exams on Benmouna showed no sign of violence. The young man died of "cardiac arrest by suffocation" after hanging himself from his cell's plasterboard wall, the prosecutor said.

Interior Minister Brice Hortefeux also said it was a suicide. "A young man was detained as part of a probe into extortion. He was put in detention, and during his detention, he wanted to commit suicide and unfortunately, he did so," he said on RTL radio Friday.

Officials are particularly alert to violence between youths and police in suburbs surrounding large French cities since unrest spread across the country in 2005, triggered by the deaths of two teens trying to escape from police in a Paris suburb.

Those riots primarily hit poor housing projects where young Arab and black men with roots in France's former colonies exploded in anger over discrimination and disenfranchisement from mainstream French society.