On the recommendation of several British fashion editors, I visited Vestiaire Collective, the Paris-based resale (translation: the clothes are preowned) site that launched in the U.K. last spring and now ships to the U.S. The selection is thoroughly high-end (celebrities Sophie Dahl and Rachel Weisz have donated goods), and each piece is vetted by in-house specialists who are trained to weed out fakes.

WSJ: The Fashion Piece That Got Away