Yann's place is situated in a lovely area, a short walk from the centre of Brussels. The flat is very clean and tidy with very good working amenities.
However the listing suggests that it is suitable for 5 guests. The bed is okay for 2, the sofa bed sleeps 1 Adult at a push and the futon may be suitable for 1 Child. Check in was tricky as the keys are in a lock box across the street, and it isn't obvious which flat is 18-20.
That being said Yann replied very quickly which made the situation much easier.
All in all I think Yann's place is perfect for a group of 3-4 to stay for a few days, if you are looking to explore Brussels.