It is x-small to small, size 34. Usually jackets like this are too big and boxy, this leather is fairly rigid like a proper motorcycle jacket should be but fits like it should - no too tight and not too loose. Shoulder seam to seam is approx 15 to give you some idea.
My chest is 34D and I can zip it up, it would be best if you were slightly smaller than me on that front but I definitely wasn't uncomfortable with a woven shirt under. The item "Acne Studios Merci Black Leather Motorcycle Jacket 34 Small" is in sale since Sunday, May 22, 2016. This item is in the category "Clothing, Shoes & Accessories\Women's Clothing\Coats & Jackets". The seller is "napsandchocolate" and is located in Brooklyn, New York. This item can be shipped to United States.