Good memory Maya! I found sizing to be a little odd. I ended up buying that coat in a Small, and the sleeve length and overall cut seemed to be pretty TTS ( I usually wear a 4 in most brands). The one glaring exception to this was the very narrow cut across the upper back. The coat buttons across the bust just fine, it's the narrow cut right at shoulder level.
I tried a Medium for fun and while it was obviously a bigger size, the shoulders were nearly as tight as the Small.