First interview to offer was under a month, although I have heard this is unusually fast for Evonik.
One interview with HR and line manager only. No big surprises, all the usual interview questions - why are you interested, why are you a good fit, etc.
Second interview was 1 hour, with the same people as in the first interview, plus another senior colleague unrelated to the job function. This was competency-based.
Third interview was 90 minutes long. It was with same colleagues as first interview, plus the line manager's manager. I had been given a presentation topic beforehand and asked to deliver a 15 min presentation. The rest of the time was taken up with discussion.