I was told all buildings in the old town are listed/protected. Is this true?
All buildings within the Main Square and streets around it are listed, the rest is protected or listed. You need to apply for the permission if you want to change something outside the buildingin general
(like the windows, colour of elevation).
I would advice to check what is listed in case of this building as it may turned out that there are some adornments inside the apartment and you will have to apply for the permission in case of any changes in the apartment. It may also be written that only the renovation of the common parts of the building needs permission.