Nouméa car rental at airport

Is there any car rental agency open at Tontouta Airport at 6.00 am and at 9.00 pm? Websites say to be opened at around 7.00 am and closed at around 6.00 pm, but I'm not sure whether this is related to the town or airport offices.

Not sure if you are talking about picking up a rental at 6am or not but we dropped off our car(rented from Avis in Noumea) around 6am and were told just to leave it in a particular area of the parking lot so I'm assuming they did not open the office until later.

Thank you newfie! Now at least one of my two problems is solved.
Here in Europe, various companies told me that their offices at the airport are open 24h a day, but I hardly can believe that, since at much bigger airports than Nouméa this service is not offered.