I definetely recommend this flat, which is very comfortable, well furnished, and corresponds exactly to the photos. It is located in a quiet neighbourhood, close to Santa Catarina street (pedestrian shopping street). Count 10 minutes walking to go to Praça da Republica and a good 20 to go to the Douro river.
João was great host, he welcomed us perfectly and gave us a lot of advices about what to do in Porto.

Our to-do list in Porto : walk and get lost through the streets, rent a bike and bike along the Douro to get to Matosinhos beach, surf at Matosinhos, take a boat on the Douro, taste Port wine and green wine, go to a champanheira and enjoy the portuguese food!