Structure of the flat: From the 2nd floor of the staircase you walk directly into a large open living room with a kitchen. There are 2 separate bedrooms. One bigger, with a double bed and a small balcony facing the main street. One smaller bedroom, with 2 single beds (these were a bit uncomfortable and squeaky). There is an expandable sofa in the living area as well.
The Cons: steep and narrow staircases towards 2nd floor (no elevator) so be prepared if you have big and heavy luggage; squeaky floors and thin walls; looks like some things are masked or renovated in a rush, with poor quality and fake walls; you can hear the footsteps/trepidation from the above flat (probably the same feeling for the flat under); no TV; no bathtub
The Pros: very good location if you plan to walk and/or use public transport (very close to the European Commission); lots of various shops (night shop for groceries as well), restaurants and services nearby; near to parks and museums; walking distance to Schuman metro/train station; there is a lot of light from the big windows, very warm when sunny. Spacious and cosy living + kitchen area; easy and well equipped if you need to cook something. Very good communication with the host.
It is good for a short stay, but it is the type of accommodation for which you pay for its good location rather than for the comfort.