Joséphine’s flat is so lovely. Really stylish place, and a really nice place to stay. Very welcoming, and Joséphine was a great host.
The area the flat is in was great - not far from the main sites but also with it's own things to do (cafés etc). The days we were there we didn't end up using the subway (it was during the fêtes does Lumieres, so the subway was too busy when we would have used it), but the station is close by. If you're walking note that it's either up hill or a lot of steps, but only a 20 mins walk from Hotel de Ville.
Joséphine left us some fruit etc which was a really nice touch, and gave us loads of great recommendations for good places to eat - including a lot of veggie and vegan places which was perfect for us, as well as some more traditional places.