It's all in the subtlety, quality, and fit. And yes, the lack of body fat helps. There is no overestimating just how refreshing it is to North American eyes to see the combination of a good hair cut, minimal make-up, and flat shoes on beautiful women who don't stuff their sexuality down your throat. Don't forget too: excellent French lingerie under it all, giving the right sillouhette.
There's something to be said for spending your entire budge on 4-5 great pieces a season, wearing them everywhichway, and truly making them your own. I think we North Americans get so caught up in finding a bargain at Winners and the like that we end up with closets full of ill-fitting crap. I've experimented with the former approach the last couple of years and have found dressing to be far more satisfying and personal. Dressing for self rather than in hopes of getting in the Ins and Outs columns in Vice (or Glamour, depending on your personal tastes). Subtlety doesn't get as much attention from the masses, but those who know will notice...