Outrage is growing in France over the decision to bring manslaughter charges against a jeweller who shot and killed an escaping robber but the country's top security official urged fearful storekeepers to let justice take its course.

Stephan Turk, 67, has been put under curfew at home with an electronic tag after the shooting last week that left a teenage robber dead outside his jewellery shop in Nice. An accomplice escaped on a motorbike.

In a country where gun violence is rare but thefts are increasingly common, the shooting has placed the government in a difficult position.

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"Even when faced with the unbearable, we have to let justice prevail," Interior Minister Manuel Valls said in Nice, where he was sent by the president a day after a protest by hundreds of Mr Turk's supporters.

Jewelers in southern France say they are being targeted as never before and lack the resources to protect themselves.

"It was a difficult situation. I don't know how I would have reacted myself. I don't endorse what he did, but he had been beaten and threatened with death," Yan Turk, the son of the jeweller, said. "We've had it with being targeted by robbers."

France has seen a spate of high-profile jewelry thefts lately.

A single gunman in the southern city of Cannes took an £85.5 million cache this summer. That was followed by another armed robbery days later in the same city.

"The number of jewelry store robberies has been climbing for years. There's one robbery a day in France," Christine Boquet, president of the union of jewellers and watchmakers, said. "This creates enormous stress for the merchants. They live with this fear and insecurity every day."

But the sister of 19-year-old Anthony Asli who was killed says Mr Turk shot him in the back and deserves prison.

"He shot a kid in the back. He's a traitor, he's a coward," said Alexandra Asli.

Aslihad been convicted 14 times in juvenile court but Bedos, the Nice prosecutor defended his decision to bring preliminary charges Friday against Mr Turk, who, he said, had an illegal gun.

"After he was threatened, the jeweller grabbed his firearm, moved toward the metal shutters, crouched and fired three times. He said he fired twice to immobilize the scooter and a third time he fired because he said he felt threatened," Mr Bedos said. "I'm convinced that he fired to kill his aggressor. When he fired, his life was no longer in danger."

AP