Fairly easy. First I did not receive any response from the HR team, but once I contacted them again everything went very quick and I received my internship offer within 1 week.
First round: Telephone interview with intern representative. He was very friendly and asked the normal fit questions. First I had to go through my CV and talk about my background. Then I was asked why I want to work for the company etc.
I heard 2 days later that I was in the next round.
Second round: Personal interview with the team lead and team manager of my potential team. Again very friendly. Basically same procedure as the first round. However, this time I had to identify a target group according to a product they gave me.