It is not really a change. He has said only what is obvious for years considering evolution of our weapon toward more accuracy, reduced/variable yields warheads and improved targeting using satellites (M45, TNO, ASMP, Hades, TN90 ...) http://nuclearweaponarchive.org/France/FranceArsenalDev.html You can notice that moderate left did say nothing about Chirac statement and did not exploited it. Chirac speech is only a warning for Iranians and other state supporting terrorist groups and in internal effect, towards French to remember necessity of nuclear weapons. Doctrine is only a verbal declaration.What matters really, and all governement know that, are capabilities.In real war, former verbal declarations do not count. France doctrine is volontarly vague. There is 30 years that our REAL doctrine is counter force, first to industry and some startegic targets (airfields, harbours) then with increase of accuracy , toward more hardened targets. All experts know that France is developping new generation of warheads like US (bunker buster, enhanced effect weapons, reduced yields weapons) just in case.