First I had a call with HR, who responded quickly to my application. Followed by a 1st technical interview short after. Both went well, but after almost 4 weeks no update (they did mention this during the interview that it would take a while).

The process was quite long. I had to first submit my recorded answers to generic soft skills questions then I was contacted for a first interview with the hiring manager and an engineer where I was asked technical questions. Next round was with a technical presentation in front of many members of the team. There the questions were more aggressive but I could really feel they were prepared even on topics which were not central to their work and I definitely appreciated that. Another step was then with the H&R (as a follow-up from the first one) where I was asked to fill-in a questionnaire which we discussed during the interview. Last step was with the group leader where she did most of the talking about how things run there and what to expect in the first few months and so on. The generic impression was that they care a lot about the person during and after the interview. They contacted me even unofficially to see whether I was still interested and if I had more questions and to give me feedback about the interview rounds. The overall difficulty was medium-high but it also depends on how well you know your topic (for me the presentation was about my PhD project) and all the side topics associated.