I applied online. I interviewed at European Commission (Brussels)
Interview
It is not common for European Commission to run interviews for internship positions in most of DGs, however you may be asked to participate in one. You would be asked about your experience, knowledge of EU institutions and motivation.
I applied through university. I interviewed at European Commission
Interview
Breve colloquio telefonico della durata di 25 minuti con domande motivazionali e tecniche. Risoluzione di due casi specifici per la unit di riferimento e richiesta di proporre un approccio di analisi.
I was a bit nervous. You need to have an excellent command of English, because the topics of the questions varries. Try to answer only about that you are questioned for.