It seems to me that the French unions are exercising their teeth considerably more than U.S. unions, generally speaking. It's hard to find any really in-depth, convenient coverage, but according to
this article in the BBC, it looks like public transportation unions are actually taking concrete steps towards forcing their perspective (i.e. wrecking railways).
Although my understanding of things is partial to say the least, I envy this level of conviction, and wish U.S. unions would stop screwing around and start taking a harder line themselves. I am a non-union worker (and largely screwed because of it), largely for this reason.