Luiz is just a great host!
He greeted us with delicious home-made lasagna, gave us many good tips about Rio, offered several rides in his car... a REALLY nice guy, sharing, simple, friendly and easy-going (his self-description is thouroughly true! :-).
In brief, we were almost feeling at home.
And, by the way, the location of the flat is perfect to visit the city (many buses and metro), in a nice area, and the flat as well as the guests' room and bathroom are very very nice, with a great view on trees and plants!
Meeting Luiz was just great and we indeed hope to see him again, maybe in Paris: Luiz, you are welcome!