I stayed four nights here and had a great time. It's a decent size by Paris studio standards, with lots of light from those two big French doors, looking out over a quiet courtyard, with trees and sky in view.
It's been recently renovated, and they did a good job, with marble finishes, a kitchen with all you'd need to cook for a short stay (fridge, two hotplates, all the tableware and cooking things you'd need - sure it's a microwave not a conventional oven, but who's cooking a roast or a cake in a Paris studio on holiday?) Good bathroom, good shower (I would move the curtain to give more room in the recess) and good quality new washing machine & dryer.
One reviewer said noisy... really? It's so quiet, it faces away from the street. Sure there's a bit of creaky stair sound at times, but I never heard any loud neighbour noise and certainly none late at night. If you live in the city it's what you'll be used to.
And such a great neighbourhood! Rue Oberkampf is lined with local bakeries, deli, butchers, there are bars from old school local where men drink brandy with their morning coffee, to cool hipster places with north African menus prepared by a Moroccan chef. A strip of late night bars and clubs two streets over in J P Timbaud, and up to Belleville, very multicultural, lots of Asian and north African businesses and restaurants. Not far to Plaza Republique, you can walk all the way along Canals St Denis et St Martin to the gorgeous Parc de la Villette.
And going the other way towards Le Marais and the centre and the big tourist draws, it's very close, walkable or just a few stops on the metro. If you arrive on a train at Gare du Nord it's 10 minutes by metro or under 10€ by uber.
Communication with Olivier was quick and clear. I was on a Eurostar train, arrived late, and by keeping in touch with him re revised ETA, Sal met me on arrival. Olivier was happy to accommodate a late checkout once it was clear there wasn't a guest checking in that day.
It's not cheap, but housing in Paris is expensive. If you want to be comfortable and are prepared to pay for it, this is a great option.