Samuel's flat was exactly as described. It is a lovely little apartment, bright and clean. I stayed with my two grown sons for a week in early September. The weather was very hot; a ventilator and a column ventilator were provided. As noted in the comments, the area is very noisy at night; I knew to expect this so it was OK. As it's hot, we kept the windows open so the noise was not shut out. During the week, the partying stopped around 2 in the morning; on the weekend, around 3: people singing and talking. Around 8 am, early morning sounds start: hammering, garbage collection, etc. Dear future visitors: just so you know. It's quiet in the afternoon. I used ear plugs the first night and then got sort of used to it.
The up side to the noise issue is that you're right in the centre of a very lively area; 2 minutes walk away is the look-out point Santa Caterina which collects a crowd of young and old people every evening to watch the sunset, listen to music and drink beer or a cocktail: a highlight of our trip, and right on the doorstep. There are also restaurants right on the street and nearby.
The flat is comfortable enough to relax in during the day and evening. There is a simple stove top where we made cooked breakfast with eggs and bacon purchased from the Minipreco supermarket just up the street. The street, btw, is very steep, as are many streets in Lisbon. You can hang your washing up on a washing line outside the window (the flat is on the first floor) and ours dried very fast. There is a filter coffee maker, sugar sachets and salt. The shower has hot and strong water.
This is a very pleasant, relaxed flat right in the centre of Lisbon. I recommend it warmly to everyone, as long as you know about the nighttime revelry.