My interview took 45 min or maybe one hour. You just need to be prepared and don't try to impress with complicated answers. Be able to understand a patent text in all three languages! Don't answer a question if you don't understand the question, ability to details is an important skill for examiners job.

The EPO selection process has 3 stages. Online test for personality and logic. Apparently personality does not really matter at this stage. Then skype meeting to discuss patent with your future coworker. Then you skype with an external worker which test your personality. Beware if you are a little bit creative of have a little bit too much of personality. They are looking for malleable people to follow their direction. Finally you get to meet the people in persons. This is when they almost harassed me and I was saved by another person who was in charge to check the interview process was fair. This job has nothing to do with innovation, you will get to scroll down and read a certain number of patents per day. They also are looking for very diligent people who will stay forever with them and follow whatever direction they are told. In my case I was applying for a certain technical field for which I got accepted and got the technical interview in another technical field. I had prepared the technical interview for weeks by learning the relevant vocabulary in the 3 languages and had a technical interview which had nothing to do with that. They suddenly to change the field without letting me know in advance. To me this was truly unprofessional. I had the same feeling of lack of professionalism when they invite me to come to the interview a week in advance but gave me half of the money to pay a plane ticket. I had to request more money and it worked and I can imagine some shy individual would not do so. Please ask for them to reimburse the full cost of the interview. In my case I would have paid about 1000euros out of pocket to come. Finally the real live interview was shocking with references to slavery as a joke about the job and pushy personal comments.