Great location, really close to porte du Narmur, 20 minutes foodwalk to city centre, very close to the European Quartier/European Commission, grocery shops etc. The street is very quiet at night. The appartment has all you need: kitchen, fridge, bathroom etc. TBH, it's quite cozy!
Leo and his friend are great hosts - very quick in responding, very thoughtful and accommodating.
Warning - as Leo described in his post, the stairs to the apartment are quite steep. I had absolutely no issues getting up or down, and no issues getting my luggage upstairs (young woman, no very strong), but as Leo said, people with mobility issues might want to stay clear.