A group of French shopkeepers appeared in court on Thursday to protest against a controversial device which disperses young people by emitting a high-pitched noise only they can hear.
The "Mosquito", developed by a British inventor whose daughter was harassed by youths hanging around a local shop, emits an irritating high-pitched pulse that most people under 20 can hear but almost nobody over 30 can.
Its creator Howard Stapleton says he has sold around 4 000 units in Europe and North America, including in France where the device has been rolled out under the name "Beethoven".
But a group of traders from the town of Pleneuf Val-Andre in Brittany in north-west France, took legal action after one of the devices was fitted on a local house, calling it an "illicit sound weapon."
Several residents claimed to have suffered sudden headaches since the device was installed, while children were seen covering their ears as they walked by.
The owner - who claimed he was the victim of vandalism and anti-social behaviour on behalf of local youths, has unplugged the device pending the court ruling, which is due on April 30.
The Mosquito has provoked protests from several civil liberties groups, while about 7 000 people signed an Internet petition to ban it in Europe, although the European Commission has said it would not introduce a ban.
Stapleton says he supports regulation on its use, insisting he "never intended it to make kid-free zones".