I ordered a L based on the size chart. I'm an American size 34D. The cups are a size or two too small for me. Going to try a different style is a size up since this one is now sold out :(
it was my first purchase from the brand, I was skeptical about sizing, fit and finishings, to my surprise I received a beautiful bran carefully crafted with a delicate adjustable band. It's comfortable, beautiful and I love the adjustable closure.
I usually wear a 34C and went for the size Medium, fits great, I love that the back is adjustable.