It's a nice flat which has everything you'd need. It's the perfect flat for exploring the hell out of Paris.
It's easy to find; and to get to and from, because the Phillipe Auguste Metro Station is nearby (don't bother with the app, or the Navigo Card; know which station you're getting off at).
It's next to Pere Lachaise, which is beautiful.
There's a Velib' bike station at the end of the road (get the app), and an ALDI round the corner.
There's a nice Boulangerie, and good places to eat; across the road down Rue de la Roquette.
Hervé was very communicative, to the extent that he helped with directions from CDG, got us an fan to deal with the heatwave, and helped us within minutes of locking ourselves out.
Also the price is fairly reasonable by Paris' standards. Can't really fault it.
DO NOT MESS WITH THE LOCK IN THE DOOR KNOB.