The P400-class patrol vessels are small patrol boats of the French Navy. They were designed to accomplish police operations in the French exclusive economic zone (EEZ). They were built by the Constructions Mécaniques de Normandie, which specialise in small military craft. Two similar ships are in service in Gabon. The P400 class were originally designed in two versions: one armed with Exocet MM38 missiles, and another public service version with a smaller 16-man complement; eventually neither of these versions were commissioned as the French Navy chose an intermediate version.
All of these craft were based in overseas territories (DOM/TOM) where they conducted sea monitoring missions and secured the EEZ. They also executed missions in the context of French agreements with other nations, typically supporting foreign armies or carrying out humanitarian missions. Since late 2008, ships of the D'Estienne d'Orves class, with their heavy armament removed, were planned to replace the P400 in the high sea patrol role, a task for which the P400 class have proved to be underweight.