A useful thing to do is to contact someone who graduated recently (ideally from your home country or even undergrad university) and ask them. Generally, people are quite responsive.
Basically, you should expect questions about your background, demonstrate good knowledge of current economic and political situation, show strong motivation and ambitious but achievable goals. All of that while not sounding boring

. Everyone I asked said there aren't going to be any technical questions, but you never know.
Also, people tend to have really different impressions, it heavily depends on the interviewer. Some say, that the whole process was rough, even slightly rude. Others claim that everything went smoothly. So be prepared and do not freak out)