Having ordered a few pairs of pants from Yoox before, I can say naturlaut's guess is right. It is a little random as to which pants fit this sizing scheme and which fit the standard American one. The way to figure out what you need to order is to filter everything by your approximate size. For example, I'm roughly about a medium in generic terms, so I searched for only "medium" range items. Then, some pairs of pants stocked in only size 32 (my waist size) would come up, and you could tell those would be U.S. sized, while some pairs that would filter through would be only available in size 38, which translates to It 48=32. So if the Dior pants are only available in "size 36" and pass through the filter when you look for "small" items, it would probably be your size. This should work for you, and if it doesn't Yoox has a good reputation for dealing with returns.