Thanks for your answer,
The problem in my case is that I have very few professional experience (5-month internship in an NGO in Berlin). Therefore, I find it very difficult to enter organizations such as the World Bank, UN, etc. who usually require applicants to have some professional experience. Same concerning major NGOs. Moreover, and here is the big issue for me, it appears that most of IR-related entry-level positions are looking for people with master degrees in IR, political science, or economics. A business degree does not seem to fit. That's why I'd like to apply for an MPA/MPP/MA in IR in a few years, as it would give me the opportunity to enter these organizations. However, if there's an opportunity to get a job there without having to go through another degree, I'd be very interested to know about that. But as for now, I have found nothing that would allow me to do that.