Thoroughly deserving of a five star rating. Jean-Luc is an excellent host. He happened to be in Lisbon when we arrived and was there to greet us: he's a really nice guy. He also arranged taxi transfers from the airport (which is only 15 minutes away). The place is certainly within walking distance of the city centre attractions - we walked in on the first couple of days to the castle, botanical gardens and main square - but Lisbon is very hilly and the streets rather higgledy-piggledy, so eventually you'll want to take public transport. The metro / bus stops are less than ten minutes away.
Lisbon is wonderful, but the highlight of the trip for me was Jean-Luc's garden. One hundred foot or so long, and very lush, connecting the apartment to the house. We picked some oranges from the tree and had freshly squeezed juice one morning, and tended to eat there in the evenings rather than going out, as it was just so lovely. The house has a lot of character, and the apartment a great sitting / dining room which gets the sun in the mornings. The kitchen is well equipped, some good big pots and pans, and both bathrooms pretty stylish. WIFI worked well in the apartment, and I liked Jean-Luc's record player in the house, with its collection of 1980s albums. Top marks all round really.