I didn't do any interview. I only applied for the intern position through the application form on the UN career website online and got hired after roughly 5 months. It was super easy, although it was for an unpaid internship.

I was informed before the interview that it would take no more than 15 minutes, and it didn't. The interview was friendly and very to the point. It was a little difficult because the two questions were broad and asked as one.