I had the luck of directly getting the final round due to career fair and I was also an final round candidate for an full time role, and hence I leveraged that networking into getting the Final round with Case study interview for 1 hour and I presented it indepth and answered all the questions and the vetting process is really thoughtful as I also was an previous candidate I did not need all the rounds of interviews, but the preparation of the case study was important too, at the same time there are mostly 3 rounds for selection and I would say I did well because of the indepth preparation required for the case study, and the final panel is with 2 Senior Team Members who are thorough with their experience and will grill on the on the job related decision making and the will to join the company through efforts and your own understanding of the Zalando culture, basically fit questions too.