There were three interview phases after I submitted my application. First I was called by a local talent management person (aka recruiter) and we set up a half hour interview in which he talked me through what Criteo did and asked some basic questions. Next I was invited to a video coding interview. This was done on Skype but we used an online code collaboration tool for the coding. It was basically a text editor since they were testing my ability to think and talk about algorithms. No compiler was used to check my code. The final stage took 4 hours in the office: two 1 hour sessions of whiteboard coding, 1 session of system design, and then an interview with the hiring manager. I also got a nice guided tour. The overall process was very smooth. It took longer than expected because of the Christmas holidays. The people I talked with were amazingly helpful throughout. Check out their web site since the process is well documented there.