LYON, Sept 6, 2025 (BSS/AFP) - French prosecutors in the city of Lyon said Friday they had charged and detained seven people over the alleged kidnapping of a Swiss man for a cryptocurrency ransom.

The seven suspects -- six adults and a 17-year-old -- were charged and taken into custody after investigating magistrates in Lyon questioned them on Thursday.

The prosecutors' office did not specify the charges, but it had said on Thursday they were being questioned for kidnapping, false imprisonment and extortion by an armed gang.

Officers of the elite GIGN police unit freed the 22-year-old man last Sunday in a raid in the city of Valence, southeast France, the prosecutors office told AFP.

He had been abducted the previous Thursday and once the alarm was raised, around 150 gendarmes were mobilised in the operation to find him.

His abductors had been demanding a ransom be paid in cryptocurrency, said prosecutors.

Swiss police said in a statement Friday that the affair might have had its roots in a dispute over digital assets.

They said they had contacted French police after having received a tip-off from an anonymous source a day after the kidnapping.

The victim, who lives in the Vaud canton of Switzerland, had been seriously beaten up while he was held, the statement added.

French authorities have been dealing with a string of kidnappings and extortion attempts targeting the families of wealthy individuals dealing in cryptocurrencies.

In January, kidnappers seized French crypto boss David Balland and his partner. Balland co-founded the crypto firm Ledger, valued at the time at more than $1 billion.

Balland's kidnappers cut off his finger and demanded a hefty ransom. He was freed the next day, and his girlfriend was found tied up in the boot of a car outside Paris.

In May, the father of a man who ran a Malta-based cryptocurrency company was kidnapped by four hooded men in Paris.

The victim, whose finger was also severed by the kidnappers and for whom a ransom of several million euros was demanded, was released 58 hours later during a raid by the security forces.