It was a structured interview. It lasted around one hour and consisted of a set of behavioural interview questions. In my case, my interviewers were a bit serious and made me feel tense. I was asked technical questions related to my background in infrastructure design projects, and sometimes very specific details like a coefficient of something. Overall the experience was good. However, I think my interviewers didn't have much experience in this kind of processes. At some point, I felt more like I was on a test than potentially getting to know my future colleagues.