I first got in through a senior member from the consulting team who I met while working as an intern for a major European client. He put me in contact with the department of interest to me. They were very quickly interested in my profile and a series of email exchanges followed. We setup a first phone interview with the head of department. It lasted around one hour and consisted of a background check and some questions about my knowledge and my experience. I also got briefed about the particularities of the position and was asked a few questions related to my abilities to tackle them. I was recalled in twice, having a set of two interviews each time, one with the head of department, alone, another one with a senior member of research, and another one with the head of development. Then on the second day, I had two interviews, this time the director of the company's product branch (there is a consulting director too) was there with the head of dept. The level of questions was crescendo and got quite high technically towards the end.