Identity Card or passport enough for those who stay in French territories. A return or continuation ticket is theoretically required to entry. For those who want to continue their journey in the ex British islands it needs current valid passport and return ticket

Customs

Routine controls, even for those returning from free ports as san-Martín and Saint Barthelemy (attention to cameras).

Post and telecommunications

Mail works well to the West Indies. However, if your shipment is urgent, use Chronopost. Letters and cards should carry word "airplane".
Time is three to five days.
Outside the post office, the stamps are difficult to find, causing considerable waiting ranks.