well, in the book isn't Laurent supposed to be a french white guy? but i guess they changed it a little bit in the movie. and since he was a black human, he would still be black as a vampire. just lighter then usual.
In the book Laurent represents the mediterranean French type. Although coming from the African ex-colonies and the Carribbean there are a lot of black French people. Although they seldom have typical French names like Laurent. And दिया that Laurent is an old vampire, it is rather unlikely, that he is black. Anyway, black people don't really pale, as far as I've seen it. So...
RACIST!! लोल just kidding, of course! *ahem* Excuse my weird sense of humor..= P
Anyways...
I'm guessing that he was black when he was human so obviously he stayed black when he was a vampire. But ya, I was confused about that as well, I thought he was supposed to be white; I guess the movie changed it या something.