Some noise from the bar below as stated in other reviews but if that keeps you awake, go join them, as it's an awesome bar with a great high end, specialty Tequila selection!
The apartment was exactly like the photos and great for 5 friends, the location is perfect and is a short distance to all the fun and attractions of Lisbon.
Lisbon is a vibrant lively city and anywhere in that close a proximity to the main districts will have some noise at night, but the mornings were quiet.
If your going to Lisbon for an early night and to read a book maybe try a different city!