Convenient location, just a few minutes' walk from Gare de l'Est - perfect if you're taking a distance train to/from the east, but it's also along several metro lines.
The room was indeed a cosy size; perfect for one person to move around freely (though it would be tight for two people, especially the bed). It's actually larger than a lot of boutique hotel rooms in Paris.
The bathroom was very tight (very easy to bump into the towel warmer; rainfall shower head seemed oversized for the stall, so water often spilled out), .
The room was reasonably clean as far as Airbnbs go, but don't expect it to be sparkling clean like a hotel; there was a bit of mould at the edges of the shower.
WiFi speed was 220Mbps down, 39 up. I didn't have any problems with video conferences at the desk, though there are some areas of the room where the signal was weak. However, there is no power outlet close to the desk, so I would recommend a long extension cord.
The washing machine (bring your own detergent) was very convenient to have.
The bathroom could have been better equipped with toiletries: There was no shampoo, only body wash, despite being shown as included in the listing; there was only one, not-full roll of toilet paper; and there was very little hand soap left in the container. These things are easy to find on your own, and I probably could have asked the host for some of these things; but it was not ideal when my train was delayed until late at night, when stores in the area were closed.
The host was always extremely quick to respond - although she wanted to use WhatsApp instead of Airbnb messages, so this is something to keep in mind if you don't have a WhatsApp account, or if you have an Airbnb dispute. She was even kind enough to order a mattress topper for me during my last week here.
Overall, this is a nice budget spot to spend 1-2 weeks in Paris.