Three teenagers in New Caledonia have been detained suspected of being involved in last week's massive fire in an industrial zone of Noumea.
The blaze engulfed the plastics and paper businesses Cellocal and Sofaplast, burning 100 tonnes of highly flammable material.
It took about 100 fire-fighters 40 hours to bring the fire under control.
The effort prevented the flames from spreading to an adjacent tyre business.
About 60 employees were affected by the fire at the businesses which belongs to the Lafleur group.
Investigators said the fire seems to have been started at rubbish containers.