Police had to be called in to restore order at Geneva’s notoriously overcrowded prison, Champ-Dollon.
Around 20 prisoners refused to return to their cells after exercising in the yard on Saturday afternoon.
After several hours of negotiations, the police were called in at around 8pm.
The police say the operation went smoothly and all prisoners were in their cells by 9pm.
It’s not known what their complaints were.