The European Commission is a pretty powerful body and a job there, especially at the administrator level is a pretty prestigious thing. However it's also hard to get. To get on the reserve list (basically a waiting list) you have to pass through 3 rounds of exams. After each round a large number of the applicants are eliminated.
The first round was a computer round, where you did 3 tests: a test on EU knowledge, verbal test and a numerical test. (in your main foreign language: English, French, German) Then the second round is a grueling 6 hour marathon, where you do written tests on your specialty. So if you're applying as an economist, you do the test on economics. You do a test on economics theory and then write essays on economics topis, one in your foreign language and one in your native language. The third round is an oral interview with a panel of interviewers and they can ask you all kinds of questions from basic CV and personal history questions, to questions about the EU or economics theory (if applying as an economist).
And then if you pass that then you are on the reserve list. So by passing the tests it's all smooth sailing to a job? Not exactly, you can be on the reserve list for years and aren't guaranteed a job and even if they call you for an interview, you still have to compete for the position with a large group of other applicants.
They are now reforming this system and are going to set up a new system. Hopefully they will still renew the old reserve lists as there are still many people on them.
"EU to speed up recruitment in global 'war for talent'." Euractiv
EU to speed up recruitment