Let's start by stating a fact: Pants sizes are an at least two-dimensional affair. You have the waist and the length. Both are correlated, but not so strongly that it would be effective to make a one-dimensional measurement out of the two. Obviously, some are fatter than others. (For example, unfortunately, my waist length has gone from 34 two years ago to 38 these days. :( My legs, however, have stayed the same 36 inches they've always been.)
Some parts of Germany's textile industry, however, seem to think that one size number for pants is enough. When the above fact struck them (and I suppose it must have struck them pretty hard), they apparently panicked and thought of a very ad-hoc fix for the situation: Take the pants sizes as they are and double them to mean "longer legs and thinner", and halve them to mean "shorter legs and fatter". That's one way to conceal two dimensions in one. And it yields a very amusing nonlinearity: I can typically wear pants sizes between 54 and 106. Minus the range between 56 and 102. :)
But it gets worse. Apparently, C&A figured out the above fact, but too late. Within the same stack of pants (from the same manufacturer!), we found:
People, get a grip. I know that nobody's listening, but for once I suggest Germany just adopt the American 2D inch sizing system. It works. It's well-defined. Lord knows I'm no big friend of the Imperial system of units. But this is one instance where Germany's otherwise happily-metric system is severely screwed up.
If you wanna see what I bought, look here. (I took those pictures mainly for my parents' benefit. Not for yours. Did you really think I was that vain? ;))