I applied through the EPFL portal Took quite a lot of time until they answered. Interview was exceptionally relaxed, although not necessarily easy. They asked questions related to the fields mentioned in my CV. Next, they asked me if I knew X. I was embarrassed to say I didn't. "Perfect. It relates to Y feature in Z, can you now figure out what it's about? Great, can you now come up with some solutions?". Last, they said they want to ask me something that I didn't know. But I already knew who would win the UEFA Champions League. I have no idea why not many companies do relevant interviews like this.