France is being defiant because they're fully aware that, while once upon a time, they were a large and important country, they are currently of little insignificance to the world and can only be counted on to produce piss-poor wines and surrender the moment an invading army steps onto their soil.
Due to their lack of economic or military power, they're fully aware that their time as permanant members of the UN Security council will be up soon, and they're using it as a soapbox to draw attention and seem like they actually matter in the grand scheme of things.
There are dozens of countries that could take their seat in a second, and hopefully, France will be bumped off and be relegated to the same level of notoriety as all of the other second-rate First World nations out there.