Questione giuridica chiave
Whether the flat deduction for maintenance costs of privately held real estate may be denied when the property is predominantly commercially used by third parties.
Decisione estratta
Yes. The cantonal authority could refuse the flat deduction because the delegated rule excludes privately held properties used predominantly for business purposes by third parties.
Motivazione estratta
The Federal Act on Tax Harmonization and Zurich tax law allow a flat deduction only within the framework set by the Finance Directorate's binding general rule. That rule excludes such properties, and it is neither unlawful nor unconstitutional.