Legal questions about hanging advertising plaques (extra points for good answers)

It is best to see the on-site renderings. First, you need to understand a legal term called building separation of ownership. For example, if there are several units in an apartment building, then each owner has independent ownership of all parts. Be careful about unit connections, exterior walls, public stairs, etc. The previous owner could hang the billboard based on the owner's permission (if the area was actually on his balcony). You cannot think that you have "inherited" the "rights" of the previous owner. In fact, he has no right to use the second-floor owner's balcony. If this kind of thing goes to court, you won't have any advantage, so the best way is to negotiate. Why does the previous owner agree to the listing but not allow you to list it? I'm afraid there is still some financial benefit... ..