A delegation of French politicians has deplored the conditions at New Caledonia's prison which is overcrowded and prone to escapes.
A Greens senator, Alima Boumediene-Thiery, says basic human rights are being violated as inmates are being kept in cells where there are rats.
Jose Bove, an anti-globalisation campaigner and member of the European parliament, says five prisoners have to share a cell of just 13 square metres.
The group says the harshness with which the law appears to be applied in New Caledonia matches a colonial situation - a reference to last year's jailing of USTKE unionists following violent clashes at a Noumea airport during an airline strike.
The French justice ministry is to send a delegation to Noumea shortly to study the prison situation after a total of 18 escapes last year.