Initial briefing + 3 round interview. The initial briefing was around 30 minutes and was mostly formalities and to inform me of how the rest of the interview would go. Each of the following round was about an hour where the interviewers would ask increasingly difficult questions to find out where my knowledge would stop.

Very long and exhaustive. It transmit the feeling that the company knows what it is looking for. It was divided in two technical interviews and another interview about soft skills.