For an overview of France’s nuclear weapons consider the document French nuclear forces, 2019 by the Bulletin of the Atomic Scientists. Their preferred citation is: Hans M. Kristensen & Matt Korda (2019) French nuclear forces, 2019, Bulletin of the Atomic Scientists, 75:1, 51-55, DOI: 10.1080/00963402.2019.1556003.
The bulk of their nuclear inventory is submarine based with a small number of land-based fighters and a smaller number of carrier-based fighters.
France’s defense policy is their nuclear weapons are for “legitimate self-defense.” They have not adopted a no-first-use policy and reserve the right for a limited strike as a “final warning” that they will defend themselves.
SLBMs and SSBNs
France has four Triomphant-class nuclear powered submarines. One of these SSBNs is always on patrol, a second is getting ready to go on patrol, another has returned from patrol, and the final one is in maintenance. Article says each sub patrol is approximately 70 days.