Blanca and Christian,
After some confusion with the address of the flat and trying to coordinate a meeting place and time, we finally met Christian. The flat was very nice within close walking distance to everything. We didn't have too much time to spend in Zürich but the location was great and the flat itself was large with a comfortable bed.
If driving, I would recommend parking in Old Zürich (as it is much cheaper) and at the courthouse it is free from 9pm-8am. If possible use transit as the train station is within walking distance to the flat.