Yes, airspace abroad is classified differently. It's classified according to the atc service you receive not based on traffic. If you look at a Canadian or European chart for that matter, you will see that a lot of airports are classified as class B yet have little traffic in and out. Also another interesting point is some airports have an inner ring classified as class D and an outer ring classified as C. That's because of the radar service you get. By the way, Germany doesn't have class B airports. Munich, one of the busiest airport in Europe, is I believe class C. It's definitely confusing for someone used to the US airspace system but once you grasp the concept, you get it really quickly.