I applied online and they sent me an email a few weeks later inviting me to the first interview. I was very well-treated even if questions were a little bit difficult (or maybe I was just so nervous). After that, I had to solve a task. The third and funniest interview was with people working on the team. They wanted to know me better and see if I fit within the company culture. The last interview happened with the head of the department. He was really nice to me and easygoing. The interviews were not difficult, but the long process made it hard for me.