This could very well be in Germany or UK. Reasons can be absolutely absurd. Something like the landlord not being able to charge for the “space” of the balcony and the deciding to take access away. Another reason could be that the balcony was not to code thus is a liability but tearing it down might be more expensive than simply walling it off. There is plenty of things like that about Germany in a show called “Realer Irrsinn”