Great place to stay in old Montreal. Close to many bars, cafes and markets, everything is close and within reach. Check in was very flexible (notify them if you are checking in late or early so they can have staff to help you through the process). However, it was a bit difficult to find the building entrance, since the building name is called “The Sep7” rather than Sonder. It is across the street from Richmond restaurant and next to Ryu bar. Also, I received two codes (one from Airbnb and one from Sonder app) for the room we were staying, and the Airbnb code was the one that worked.
The sheets and room were very clean and the staff were very friendly and helpful. If you want to request a cleaning, you can do so for $99 through the Sonder check in app. The TV was easy to connect to with the hdmi cable I brought from home but you can also use chromecast if your laptop supports that. Overall, the experience was very enjoyable and I would highly recommend staying here!