A French town is to bug the streets of a crime-ridden neighbourhood, installing audio surveillance devices to relay to police the sounds of attacks or muggings.

Saint Etienne in central France is about to install 50 microphones for a six-month trial period. Audio will be analysed by computers which will alert police to suspicious sounds such as cries or shouting.

Police will be dispatched to the location of suspected crimes while other officers in a surveillance centre try to identify muggers or attackers using CCTV images. Once identified, police will then track and arrest the suspects.

The idea was inspired by a US system that uses microphones to detect gunshots in high-crime areas.

The French system will use American technology but will be more sophisticated, according to local authorities, as it will be programmed to alert police to a wider range of suspicious sounds. It will be tested in the Tarentaize-Beaubrun-Couriot district, which has a population of 7,000.

Some residents object to the trial, saying it will be a "Big Brother" system allowing the authorities to monitor everything they say or do.

Jean-Pierre Berger, a local councillor, said: “People should not be worried. We’re not going to spy on them.”