There was a written exam: a document to read and summarize and write a short analysis; and an essay on the future developing countries in the changing global trade environment. Then a panel interview with 4 people, each asked 2 questions and the last question was in French to assess my language skills. I wasn't offered the position, but after a few weeks I snooped around the directory and realised that they offered the job to an internal candidate that was already acting in the position, so basically it was a "transparency interview", which is the norm these days for a lot of jobs at international organisations.