Look at the model's height and weight on http://www.essence-web.jp/. One of their models is 178cm 64kg and always wears size 2. He is very close to my height and weight. Looking at sizing charts this puts him at about a 35, same as me.
My advice is if you're a small 36/46 and are ok with tighter fits then you could try size 2. But if you're solidly in the size 36/46 category then go with size 3.
What the H. Lorenzo guy said about Attachment sizing being consistent is very true. Of all the labels that I've bought multiple pieces from, Attachment has been the most consistent. Out of 20+ Attachment pieces that I blindly ordered in size 2, literally none of them fit me poorly.