You can go broke eating in this town. There are some fine restaurants but expect to pay US$30 for a hamburger at a hotel restaurant or other proper sit-down establishment.
There are a lot of midrange places where you can expect to pay US$20-30 for your whole meal. French and Chinese are well represented here. Look for the word "Snack" in the name of the restaurant. There is also a conveyor belt sushi place that's very good, and the chefs are quite friendly there.
The best deal in town is the Roulottes, the food trucks that set up shop every evening in the big square in the waterfront park. Every day they begin setting up around dusk. Chinese, French, and Tahitian cuisine are all well represented. You can get chow mein, poisson cru, crepes, pizza, ice cream, and because this is France, everything comes with bread. Expect to pay about XPF 1500 for your whole meal.