First, Martien is a wonderful host. She was very accommodating on check-in and walked me through all the features of the flat.
That flat is very new and is in a stylish apartment block. It's close to the Grand Place but also to the De Bruckere metro/tram stop.
It's very quiet, especially by Brussels standards. It faces an interior courtyard, so even the screaming students who were out one night could not be heard.