Lovely little place on the outskirts of Paris. Literally takes 15-20 mins by metro to get into the centre, with Gentilly station only a 5 minute walk away too. I would recommend buying a day pass, for however many days necessary, for zones 1-3 as the station is technically outside of zone 1. That seemed to be the best way to do it (a pass for zones 1-2 is unavailable from what I could see).
Gheddahi is a lovely host and lives just upstairs if there is anything you do need him for.
The apartment itself is a fine size for two people. I suspect 4 may be a little squeeze but probably doable for a short time. It has pretty much everything you would need and was well kept. The only thing we would suggest for Gheddachi is to maybe include a few english breakfast teabags in the selection (though to be fair we couldnt find any in local shops either, so maybe bring your own if you need the instead)