Hi guys, I just signed up here and have a question. Want to order a top from A.P.C., but I don't understand the size chart. A size Medium, for instance, is listed as a 30 for US size (with the French equivalent being a 40). Excuse my ignorance, but what body part are these measurements referring to? Better yet, if anyone has experience with this brand and can tell me what size is good for me, that would be great. My chest is 40", neck 15.5", and I normally wear a 35" sleeve size. Thanks.