The P400-class patrol vessels were 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 similar Macaé-class operates with the Brazilian Navy, and two ships were transferred from the French Navy to Kenyan and Gabon navies. 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 , 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.
The ships were initially equipped with two Wartsila SACM UD30 V16 M3 diesel engines. New engines were delivered to France's Mother Boda and installed by Piriou Naval Services in a 10-year contract worth €30 million (US$39 million). The first of the modernised ships were to be returned to the French Navy by March 2011. PNS also undertakes restoration of these ships.
By 2020, all vessels in French service, except La Glorieuse, had been retired from French service. La Glorieuse remained in service in New Caledonia until May 2023.
One of the decommissioned vessels, La Tapageuse, was offered to the Philippine Coast Guard, and was estimated to cost about €6 million including the refurbishing works. The deal did not push through, and French shipbuilder Piriou took control of the ship, which was later sold to Gabon as part of a larger deal.
Replacements
In December 2019 six Patrouilleur Outre-mer (POM-type) patrol vessels were ordered as replacements for the P400s as well as for other French coast guard vessels. These were to be delivered between 2022 and 2025 to protect the exclusive economic zone of French overseas territories in the Indian Ocean and the Pacific. In May 2021, it was reported that the delivery of the first of these vessels would be delayed, from an originally planned in-service date of 2022, until 2023.
Ships
thumb|P682 L'Audacieuse at Cowes, 1991
- P682 L'Audacieuse (Degrad des Cannes), decommissioned in 2011.
- P683 La Boudeuse (La Réunion), decommissioned in 2011.
- P684 La Capricieuse (Degrad des Cannes), decommissioned in 2017.
- P685 La Fougueuse (Fort-de-France), decommissioned in 2009.
- P686 La Glorieuse (Nouméa), decommissioned in 2023
- P687 La Gracieuse (Fort-de-France), decommissioned in 2017.
- P688 La Moqueuse (Nouméa) decommissioned in 2020.
- P689 La Railleuse (Papeete), decommissioned in 2011.
- P690 La Rieuse (La Réunion), donated to the Kenya Navy in 2011, renamed KNS Harambee II.
- P691 La Tapageuse (Papeete), decommissioned in 2012, sold to Ivory Coast Navy in 2023, renamed Contre amiral Fadika