So this, apparently, is the law since 2013 or so in Noumea and nearby:
- Supermarkets and other general stores must halt liquor sales at 12 noon on Friday, Saturday, Sunday and Wednesday. Selling in the morning is allowed, as is selling all day on Monday, Tuesday and Thursday.
- In addition, liquor may not be sold on the afternoon before a public holiday and all day during the public holiday.
- However, speciality wine retailers (cavistes) are exempted and can sell liquor <18%, but not beer.
- The duty-free shop at Tontouta airport is also exempt.
- All this applies only to take away: restaurants, bars and nightclubs have no restrictions for alcohol consumed in premises.
And if you're wondering "why!?", apparently the idea is to stop schoolchildren from picking up drinks after school ends (Wednesday is a half day). Asking for ID when buying alcohol, however, doesn't seem to be a thing...
Also, the rules above apply to Noumea, but local communes have wide latitude to change them and many parts of the country are more or less dry. (Alcohol abuse is widespread among in the Kanak community.)