The leather note in De Sade is similar to the one in "Black" by Bulgari (which was a favorite of mine for several years). Similarly, I don't find that this scent so much smells like black leather as it is evocative of black leather, especially when wet.
As it dries, De Sade goes through three distinct phases on my skin: it is smoky at first, and then it smells very similar to AIRS "China Moon" incense (which is described as "exotically vibrant musk"), and then it finally dries down to a soapy, just-stepped-out-of-the-shower clean smell with an underlying sweetness. I had several friends sniff me after I had been wearing it for a few hours, and they all commented on how clean and fresh the scent was.
It's not as leathery as I had hoped it would be, but I still really like it.