Four people died on Thursday morning while attempting to cross the English Channel near Équihen-Plage, authorities in Pas-de-Calais have reported.
The victims, two men and two women, were swept away by strong currents while trying to board a boat.
Their nationalities have not yet been confirmed, according to the prefect, who stressed that the details remain preliminary.
Emergency services treated another person for hypothermia, and 37 others, also rescued at the scene, were provided aid.
The incident involved a so-called "taxi boat", a tactic used by smugglers to pick up migrants directly from the water to evade security patrols onshore.
Équihen-Plage’s mayor, Christian Fourcroy, initially described the event as a "failed departure" at around 07:00.
The boat continued its journey despite the tragedy, with authorities opting not to intervene at the time, the prefect added.
He emphasised that smugglers bear responsibility for the deaths, stating that dismantling smuggling networks remains a central focus of their operations.
