An American in Provence

We are in our new apartment now, and the dog living in the apartment directly beneath us barks all day long while the owners are away. I seriously think I might go nuts and start barking myself. I called the syndic and all they said they would do is put up a sign in the entranceway along the lines of "All tenants are reminded that their dogs are not supposed to bark excessively." Yeah, I am sure that will do the trick. I might have to go talk to them (read: Alain might have to go talk to them.) But still, I am not sure what anyone can do to stop their dog from barking when they aren't around. I have some ideas, but don't want to end up in jail.