My interview was a phone call. I answered to an email and then got a phone call, which lasted 20 minutes or less given that the position needed to be filled urgently. I know that some other interns got a longer interview, but I was already selected by then. For the others, when I was present during their interview process, it involved asking their motivation to come all the way to this post, their commitment, their level of English and their ability to take care or themselves once they got here.