Nuclear warheads don't make sense anymore, as the ennemy cannot be identified as being a state : if a terrorist organisation like Al Q. attacks, where do you hit? Afghanistan? Pakistan? Saudi Arabia? I think you see the problem.
It's the same for Israel at the moment : the battlefield is Lebanon. You can't just nuke Lebanon and then just say you're sorry about the collateral damage... And you can't nuke Syria or Iran because they are not (officially) at war against you.
Besides, at the time Chirac said that, it was because he was under pressure to reduce France's nuclear capacity, too costly to maintain and ineffective in the new context mentioned above. So it was more of a political move than a "threatening" statement. I think the next president, whoever he (or she) is, will eventually reduce the number of warheads, it seems reasonable to do so.