French judicial authorities have charged a 20-year-old man in connection with a series of attacks after 20 people reported needle injuries during the filming of a televised concert on a Riviera beach in the southern city of Toulon on Friday evening.
One woman was hospitalised and police had to be called in after reports of the attacks caused panic in the crowd.
The suspect was identified by two women who said that he had attempted to assault them, leading him to be charged with aggravated and premeditated armed violence, prosecutors in Toulon said.
"At the current stage of the investigation, the suspect denies the allegations entirely, but given the witness statements, the prosecutor's office believes there is sufficient evidence to open a case," the Toulon prosecutor Samuel Finielz said.
The attacks in Toulon took place during the live recording of "The Song of the Year" show for a national television channel, which was broadcast on Saturday night.
Spate of suspected attacks
This is not the first incident of its kind.
Since the start of the year, at least 100 cases have been reported of young people suffering needle injuries at nightclubs and festivals.
Attacks were reported at two music festivals over the weekend.
Six complaints from teenagers were lodged at a festival in Belfort in eastern France after they experienced sudden sharp pain in their hands or arms.
Another seven people reported needle injuries at a festival in Vic-Fezensac in southwest France where police subsequently arrested a man, local prosecutor Jacques-Edouard Andrault said.
Most of the victims have been young women.
They often report the sudden onset of identical symptoms -- nausea, dizziness and sharp pain -- and only later detect a needle prick on their skin.
Results of the medical analysis of blood samples from seven of Friday's Toulon victims will be available next week.
No evidence of toxic substances, drugs
Cases have been reported all around the country from the western cities of Nantes and Rennes, to the south and Atlantic coasts, and the French Alps.
Authorities advise all victims to undergo blood tests afterwards and some have been given preventative treatment for HIV and hepatitis.
Victims do not appear to have been injected with toxic substances or drugs.
Police have struggled to identify the culprits or determine whether attackers are using a syringe or a pin.
Nightclub owners are beginning to feel the impact of the attacks on their earnings, as fearful young clients stay away.