Police in New Caledonia briefly closed the road south of Noumea after vehicles near St Louis were stoned and burnt cars were dumped.
This came hours after a small, peaceful march commemorated the first anniversary of last year's incident when police shot dead a prison escapee originally from St Louis after he allegedly tried to run over a police officer using a stolen vehicle.
The police removed the vehicles and checked the road before reopening it.
There have been a number of violent incidents along that stretch of road over many years, prompting discussions about possibly rerouting it away from St Louis.
It's the only road to the main island's south.