Collecting sand on French beaches is strictly forbidden.

MARIGOT:— The Collectivité of Saint-Martin would like to remind the general public that collecting beach sand for private purposes, is strictly forbidden. Beaches will be rehabilitated and the sand found thereon must be preserved. It is also forbidden to collect the sand that was deposited by the sea inland following the passage of the hurricane.
By way of reminder, the use of sea sand for housing constructions is particularly risky; it increases chances of building collapse.
Hence, persons caught in the act of sand extraction will be arrested and held accountable for their actions. Territorial police officers will be performing beach patrols.
The Collectivité would like to thank you ahead for respecting these instructions acting in the public interest.

COM Press Release

Source: St. Martin News Network