Career
Length	130 m
Displacement	9,000 tons (submerged)
Complement	115 men
Power Plant	One PWR
Power	16,000 shp
Speed	25 knots
Armament	16 M4 MSBS (Mer Sol Balistique Strategique) nuclear missiles four 533 mm torpedo tubes ECAN torpedoes SM-39 Exocet

L'Inflexible is the 6th and last of the Redoutable class SNLE (Sous-marin Nucléaire Lanceur d'Engins, "Nuclear Vehicle-Launching Submarine"). Construction began on March 27, 1980; launched on June 23, 1982, it was comissionned on April 1, 1985. It is part of the Force Océanique Stratégique (FOST) ("Oceanic Strategic Force").

L'Inflexible uses basically the same design than the other Redoutable-class vessels, but has yet benefited from technologal advances over its predecessors:

• It uses the M4 missile, which carries 6 independent 150 kilo-tonne nuclear warheads. Range it reported to be "over 4500km".
• Miscellaneous improvements were made in electrical systems, nuclear systems (improving safety and stealth), rudder and engines (improving reability and stealth).
• TIT (Traitement de l'Information Tactique, "Tactical Information Processor"), a cluster of French-designed computers and serial digital bus links for intersystem communication.
• DMUX21 sonar.
• Capability of launching the SM 39 anti-ship missile (best known as Exocet)
• Improved inertial navigation system.
• Improved internal communication system - SNTI, Système Numérisé de Transmissions Intérieures (Digital Internal Communication System)
• Miscellaneous acoustical stealth improvements
• Improved hull profile

The other Redoutable-class submarines have been modified to meet the standards of the Inflexible ("Refonte M4"). The Inflexible is to be discarded around 2008.

L'Inflexible has inspired Le Soleil ne se lève pas pour nous (No sunrise for us) by Robert Merle, a 1987 semi-fictionous book in form of a romanced documentary.