This is a really beautiful apartment, which is very well located between the Metro stations Arts et Métiers and République, easy access to restaurants, supermarkets, and bakeries, and within walking distance to the Marais (15 min). I was overall quite happy to stay here.
The apartment consists of a living and dining room, a separate bedroom (all facing the street), a kitchen, a toilet, and a bathroom (without toilet). It was very clean when I arrived, and has the necessary cleaning utensils (e.g. vacuum cleaner) to keep it clean even during an extended stay.
I stayed here during the record summer of 2018, and the apartment got very hot in July. There is no AC and no fan. The apartment is on the first floor (i.e. one stair up, not the ground floor), and it can be unpleasant to leave the windows open because smokers walk by and mopeds drive by, not that infrequently, so bad smells can come in. This improved in August, when not that many Parisians are in town.
The apartment is equipped with wi-fi, a fridge with freezer, a washing machine, and a dishwasher; you have to buy the detergent. There is a microwave oven, but during my stay the microwave did not work. The Internet connection, while pretty fast when it worked, had repeated outages for several weeks (out of my three-month stay). Because the TV gets its signal through the Internet connection, this also made the TV unusable. The letting agency did not take steps to fix this problem although I asked them to numerous times over email and phone, which I found quite frustrating. Eventually the connection seemed to fix itself, and I had a good Internet connection for the last few weeks of my stay.