The interview process took about 4 weeks, mostly because the whole company was in Paris for the summit during that time so it was difficult to schedule. It consisted of 2 in-person interviews plus an informal coffee meeting with the team lead. The only thing that annoyed me about the process was that they showed very little consideration for the fact that I was still working elsewhere and it was difficult for me to get away that often. The questions are pretty standard but it depends on who is interviewing you (it's usually several people) because everyone asks different questions. Nothing too difficult though.
The only annoying thing was that I was apparently being interviewed for 2 positions and had no idea until probably the 3rd interview. Once I told them which one I was more interested in though, they began considering me for that only. It just would have been nice to know that going in because the recruiter indicated I was only interviewing for one.
Also, the person I would be working most closely with wasn't around during the interview process which was unfortunate. I had a lot of questions about what I would be working on and nobody could really answer those for me. I kinda wish someone would have reached out to this person or to the central team in France so that I could get a better idea of what I was getting into before I was hired. This won't be the same experience for everybody, I'm sure, but just a heads-up in case a similar situation arises.