Le Redoutable Submarine, Guillaume
Rueda via WikiMedia Commons
The French submarine fleet consists of nuclear-propelled attack (SSNs) and ballistic missile submarines (SSBNs). France decommissioned its last Agosta-class diesel-electric boat in 1999 without plans to replace the class with modernized diesel-electric vessels. This is despite France's pioneering role in the development of air independent propulsion (AIP) technology. 
The French Navy's area of operation includes the North Atlantic, the Mediterranean Sea, and the Indian Ocean. France also maintains a presence near the economic zones of its numerous overseas territories and former colonies, such as French Polynesia and New Caledonia in the South Pacific, the West Indies and French Guyana in the Caribbean Sea, Reunion Island and Mayotte in the South Indian Ocean, and Djibouti at the mouth of the Red Sea. 
Submarine Tables for France
France currently operates four Le Triomphant-class strategic missile submarines (SSBNs) based at Ile Longue, Brest. Since 1991, all six units from France's former fleet of Le Redoutable-class SSBNs have been progressively decommissioned, with the final vessel, L'Inflexible, completing its last deployment in 2007.  While plans originally called for the procurement of six Le Triomphant-class vessels to replace these older units, in 1991 this number was decreased to four. The final vessel of this project, Le Terrible, entered service in 2010 and is equipped with 16 new M-51 submarine-launched ballistic missiles (SLBMs) carrying four nuclear warheads each.  The previous three Le Triomphant-class submarines are currently equipped with M-45 SLBMs, each carrying six TN-75 nuclear warheads, but will be progressively adapted to carry the M-51 by 2017-2018.  According to France's 2008 Defense White Paper, in 2016 the country will deploy an upgraded version of the M51.1, the M51.2, which will be mated with a new warhead, the TNO (Tête Nucléaire Océanique or Oceanic Nuclear Warhead). The weapon was developed on the basis of a "concept validated during the final series of nuclear tests in 1995." Originally planned for deployment in 2015, the first M51.2 missiles will be fitted on Le Triomphant-class, submarines starting in 2016.  In late 2014, the French Ministry of Defense announced that it initiated research on 3rd generation submarines, which would progressively replace the four Le Triomphant-class submarines starting in 2035.  Since France decided to dismantle its land-based ICBMs at Plateau d'Albion in 1996, its SSBN force is the nucleus of the country's strategic deterrent, and maintains a continuous at-sea presence. 
France also has six nuclear-powered Rubis/Améthyste-class attack submarines (SSNs) currently on active duty, based at Toulon. However, the class is to be gradually decommissioned and replaced with the newly developed Barracuda-class attack submarines, the first of which, Suffren, was ordered in December 2006 and is due to enter service in 2017.  The new class will feature improved communication capabilities and, more importantly, an increased force-projection capability based on cruise missiles.  France and Britain have jointly developed the Storm Shadow/Scalp EG cruise missile, which can fulfill this force projection requirement due to its high accuracy and effectiveness against hardened targets.  The attack boats' main task is the protection of France's SSBN force and carrier group via anti-submarine and anti-surface warfare. In addition to traditional sea control and sea denial operations, its attack submarines are tasked with Special Forces deployment, surveillance and intelligence gathering, and missions against piracy, narcotics, and human trafficking. 
 Interview of Jean-Charles Lefebvre, Chief of Naval Staff, by Klaus Jacobsen, "The French navy in a phase of transition," Naval Forces, 1998, Vol. 19, No. 5, pp. 37-41.
 "Maritime forces' contribution to the major strategic functions," French Ministry of Defense, www.defense.gouv.fr.
 "France Submarine Forces," Jane's Underwater Warfare Systems, 11 November 2009, www.janes.com.
 "Le Terrible Livré à la Marine [Le Terrible Delivered to the Navy]" Ministry of Defense, 4 October 2010, www.defense.gouv.fr; "Sous-marin Nucléaire Lanceurs d'Engins Le Terrible [ Le Terrible Nuclear Ballistic Missile Submarine]" Ministry of Defense, updated 22 August 2011, www.defense.gouv.fr.
 "Adaptation au M51 des SNLE [Adaptation for M51 of SSBN]," Ministry of Defense, updated 3 December 2010, www.defense.gouv.fr.
 Francois Hollande, "Discours sur la dissuasion nucléaire-Déplacement auprès des forces aériennes stratégiques," 19 February 2015, www.elysee.fr.
 Jean-Yves Le Drian, "Discours de clôture, colloque pour les 50 ans de la dissuasion," 20 November 2014, www.defense.gouv.fr.
 "France: Nuclear weapons," Global Security Website, www.globalsecurity.org; "Visite virtuelle sous-marin SNLE - Presentation," French Navy, www.defense.gouv.fr.
 "Le Sous-marin d'Attaque Futur Barracuda [The Barracuda Future Attack Submarine]" Ministry of Defense, 9 June 2011, www.defense.gouv.fr.
 Interview with Jean-Louis Battet, Chief of Staff, by Wolfgang Legien, "French Navy - ready for the 21st century," Naval Forces, 2002, Vol. 23, No. 5, pp. 8-13; in ProQuest Information and Learning Company, https://proquest.umi.com.
 "Storm Shadow/Scalp EG/Conventionally armed standoff missile (CASOM)," Federation of American Scientists, www.fas.org.
 "France Submarine Forces," Jane's Underwater Warfare Systems, 11 November 2009, www.janes.com; "Sous-marin nucléaire d'attaque type Rubis," French Defense Ministry, www.defense.gouv.fr; "Maritime forces' contribution to the major strategic functions," French Ministry of Defense, www.defense.gouv.fr.