Il principio di proporzionalità nel procedimento tributario

The thesis focuses on the applicability of the principle of proportionality to tax proceedings. It analyzes the origins of the principle of proportionality in general, then moves on to its application in administrative law, the branch of law most closely related to tax law and where the topic has been studied for the longest time. From an in-depth analysis of administrative law, the context and origin of the legislative amendment contained in Legislative Decree 209 of 2023 emerges, which led to the introduction of Article 10-ter of Law No. 212 of 2000 on the principle of proportionality in tax proceedings. The thesis then addresses the core of the issue: the applicability of the principle of proportionality to tax proceedings. Several areas of application of this principle are then identified, specifically the protection and interpretation of taxpayers' procedural rights, the obligation to adopt the most lenient of the investigative powers available to the tax authorities, the protection of fundamental rights, and, finally, the application of substantive tax law. Finally, the issue of judicial remedies in the event of violation of the principle of proportionality is addressed, from the possible inadmissibility of evidence collected in violation of this principle pursuant to Article 7-quinquies of Law No. 212 of 2000 to the possible annulment of tax assessments issued by the tax authorities pursuant to Article 7-bis of Law No. 212 of 2000.