Another teenager in the southern city of Montpellier was sentenced to four months in prison for hitting a passer-by 30 times with an iron bar overnight Saturday. The teen was also kitted out as a clown.

Complaints have poured in recently over "armed clowns" wreaking havoc in various parts of the country — some carrying pistols, knives or baseball bats — and police have detained several people over the violent trend.

The phenomenon has even prompted anti-clown vigilantism, forcing police to step in to try and quell the hysteria by saying there have only been a few sightings of the grotesque pranksters.

On Monday, a woman who had just got out of her car in Chelles near Paris called the police, saying two clowns — one of whom was armed with a fake axe — had attacked her, a source said.

They escaped when a passer-by armed with a baseball bat tried to stop them, and one of the pranksters was subsequently detained when police spotted him, white make-up still all over his face.

In a separate incident just half an hour afterwards, a dozen people wearing the smiling, white masks associated with the Anonymous hacktivist collective attacked three youths at a station in Melun, also in the Paris suburbs, stealing their mobile phones, the police source added.

Trend seen in the US and Britain

The phenomenon of dressing up as an evil clown and terrifying passers-by — a trend which has also been seen in the United States and Britain — cropped up in the north of France in early October.

In the town of Bethune, a 19-year-old received a six-month suspended jail term last week for threatening passers-by while dressed as a clown.

These "clowns" have been "mostly spotted outside schools, but also on public roads, in bushes, in a square. Their targets are often young children or teenagers, but also adults," a police source in northern France told AFP.

And the phenomenon has spread to the south of the country.  

Police on Saturday night arrested 14 teenagers dressed as clowns and carrying weapons in the Mediterranean port town of Agde.

In Montpellier, meanwhile, the victim of the fake clown told the court that the costumed assailant had chased him, yelling "give me everything, your telephone, your money, your briefcase," and added he had trouble sleeping and had nightmares since the assault.

The attacker, meanwhile, admitted he was drunk.

Theories abound as to the origin of this trend of violence in a country where Halloween has barely made any inroads.

The suggestions include a challenge launched on social networks, popular videos on YouTube showing a terrifying clown pranking people, or even a recent episode of the popular TV series American Horror Story featuring Twisty the killer clown.