The interview process was good, there were 3 phases:
1. initial HR interview
2. technical interview
3. co-founder interview
All of them were professional and no pressure was put on the candidate in any way. They listened to you and asked pertinent questions. The technical interview was more of a discussion, but it also had pre-defined questions, probably to make sure you had a minimum of knowledge in the field. Overall, a good experience. The co-founder call was also interesting, you could find out more behind-the-scenes about the company.
However, in the end the offer was a low 10% over minimum wage (which in Germany was just increasing to 12/hr at the time). Is this really a decent salary for a tech internship? In any case, I declined.