We had a great experience at Ciprea and Davide!
Davide welcomed us very nicely, despite our late arrival (00:20), and didn't charge us anything extra for that (unlike other rooms I had seen!). He speaks very good French and answered all of our questions. Except for the first message, we always had a very quick response to our messages.
The city tax is a legal matter and the hosts have to fill out a form to declare your stay to the city of Venice, which fixes the price of the tax. This was all done within the rules.
There was a mistake in the description for the room, but Davide kindly proposed us a solution to solve this matter.
The room looks exactly as shown on the pictures. Everything was perfectly clean.
We found the description was a little too short so here are a few more details.
The room is on the last floor of the house, above the kitchen. It has its own key. There are a few old guide books about Venice in the closet, and Davide kindly gave us pieces of advice.
It has its own en-suite bathroom with a shower, a sink and a toilet. There are a few things behind the mirror, which we only found when we left (too bad I had bought shampoo!). There are a two towels for each guest and a hair-dryer.
The bed covers are blankets and sheets, not a duvet. There are extra blankets in the closet in case you get cold at night. In winter, we found the room a little cold.
There is an air-conditioning system (which we didn't use, of course).
The location is great because it is in a quiet area (no crowd of tourists), but still close to everything: you can do anything by foot. The two windows are single glazing so we heard the works on the street in the morning.
As said in several other comments, there are other rooms in the house, which can be occupied by others guests, who can be noisy.
This house used to be a bed-and-breakfast, but it is not the case anymore. However, there are many things to prepare your own breakfast (coffee, tea, sugar...) in the big kitchen, with all facilities and a big table.