I had a telephone interview with the recruiter (about 30 mins) and then was invited to a face to face interview with the manager of the role in their London office. This interview lasted about an hour, and the lady was very nice and approachable. Was shown around the office after the interview and was told I would hear back within a few weeks. Fast forward three months - and I have not heard a single thing from Criteo. Even a an email to tell me I hadn't been successful would have sufficed!