The written test is approx. 3 open questions/ tasks related to the work you will do; in my case was: 1) writing a briefing note for your manager (they provided some supportive docs for collecting information); 2) preparing a PPT presentation on the briefing note; 3) preparing a budget plan in XCL, linking some worksheet. The following day I had my interview, with: 1 manager + 1 advisor from the Unit selecting the position; 1 staff from HR; 1 staff from another Unit (as moderator). The interview is a standard competency based (what do you know about Europol and the selecting Unit, teamwork, expertise in the position), they may ask you some direct examples of your past experience.