Four people in New Caledonia have been charged with organising an illicit supply of goods into the Camp-Est jail.
According to the public prosecutor, the operation was run by a prisoner who ordered cellphones, illegal drugs and food from his mother and a former inmate who collected them for distribution within the prison.
The items were reportedly smuggled into the jail by a member of the corrections staff who confessed to his role in the network.
He reportedly supplied the goods since 2018 but said he didn't get money for it as he planned to set up a business with the inmate once he was released.
The prison guard now risks up to 10 years in prison.
Reports said the activities had been investigated since March.
Conditions at the Camp-Est prison have been repeatedly decried as among the worst of any prison run by France.