We stayed in Antoine's apartment twice during out visit to Belgium. The location was great--only a couple minutes to the Grand Place and less than 5 minutes from the train station. Ideal! The apartment is pretty tiny, but well set up. It has two windows overlooking the street (which is for people only, not vehicles.) The windows open, which is great for letting a little air in. Closed they block most of the noise and the curtains help. We could hear voices from late night people, but it wasn't too bad. And the stairs are as narrow and intimidating as other reviews have said! We had small carry-on bags and had no problem, but we were very careful!
We were so happy that we were able to check in early on the day we arrived. Nice to be able to drop our luggage and freshen up before heading out. The gentleman at the Hotel Agora (where you check in) was wonderful! He gave us a spot on list of restaurants, things to see, chocolate shops, and bars and marked them on a map. Tremendous!