Size 42. I'd say it's equal to a US large. Would fit a medium though if you don't want it to be as skin tight. It's very forgiving though! from Wear Marcia: Black midi dress made from our signature regenerated fabric. Designed with slits running down both sides of the body. With buttons covered in black fabric and a hidden zip in the back. Fits true to size, take your normal size. Florentina is 1.74m tall and wears size 34. – Made in France – 100% Italian regenerated nylon fabric ECONYL®. This stretchy killer fabric sculpts all kinds of bodies. Machine wash 30° – No tumble dry