First they ask you to do a math test, you can find the questions here on Glassdoor. Easy to pass if you study a bit. Then they ask you to perform a sales pitch. A warning is in order here. If you are going to do this, you should know that it takes A LOT of time to study and prepare a good pitch, you need to be very certain that you fit their requirements before you do the sales pitch, if not you are wasting your time. They only hire very young people, so if you are above, say, 28, DON`T WASTE YOUR TIME INTERVIEWING FOR CRITEO IN BARCELONA. They will not hire you even if you do a great pitch, they want young people to keep salary expenses down. A spent a lot of time studying the product and preparing for the pitch but did not get the job, and I have been doing software sales many years with a good track record. I even walked through my sales pitch with a friend of mine who is a current employee of Criteo in Barcelona, and it turned out that I knew more about the product than him in certain regards. Overall he thought it was a very good pitch - but I still did not get the job because I was over 30. Of course they will not tell you that. HR will obviously say that they have many employees over 30, but when I was in the office I did not se ONE. Seriously. So I was quite pissed of that I spent so much time preparing, and they had decided beforehand to not hire me. SO DON`T WASTE YOUR TIME! Then they did not even call me up afterwards either to let me know what they thought. I knew that they were ashamed of asking me to spend so much time preparing and not offering me the job. But I wanted them to feel bad. So when they did not call me, I asked my friend to tell them that I wanted to know if I was going to get the job (eventhough I had figured out that I would not). So my friend who is currently employed there told HR (a french woman) to call me up, and her voice was cracking and she just said that they had found someone better. To not call someone up after asking them to spend so much time preparing a good sals pitch is very disrespectful. I am writing this as a warning - dont interview if you are above 28, you can spend your time doing something else.