Institute for Public Finance and Tax Law Fields of Research

An important basis for the Institute's activities is formed by Constitutional Organization Law and Fundamental Rights Law. For more than three decades, the former director of the Institute, Paul Kirchhof, together with Josef Isensee (Bonn), published the renowned Handbuch des Staatsrechts (Handbook of Constitutional Law), which appeared in three editions under their editorship. Since 2023, Hanno Kube and Uwe Kischel (Greifswald) have been responsible for the new edition of the handbook, which is once again set to consist of twelve volumes, each published annually. The project is supported by extensive long-term funding from the German Research Foundation (DFG).

The Institute's research in the field of Administrative Law deals with the topic of digitalization, among other issues. Hanno Kube's report at the 78th Staatsrechtslehrertagung 2018 dealt with the topic of “E-Government: A paradigm shift in administration and administrative law” (in German). Administrative Procedural Law is also the subject of research at the Institute.

Research into German Tax and Duties Law is one of the Institute's core academic areas. Hanno Kube is co-editor of the major commentary “Kirchhof/Kube/Mellinghoff” on the German Income Tax Act and the journal “Steuer und Wirtschaft” (StuW). Research on Constitutional Tax Law plays a particularly prominent role in the Institute's work on German Tax and Duties Law. This is evidenced by numerous projects dealing with, among other things, the wealth tax and the solidarity surcharge. More recently, a comprehensive Institute report has examined the taxation of so-called eco-securities. In the area of non-tax levies, the broadcasting contribution, the bank levy and issues relating to the reallocation of revenue from special levies have already been the subject of research at the Institute.

Maximilian Bowitz ("The objective net principle as a justification standard in income tax law"), Jana-Sophie Enders ("Fiscal purposes in constitutional tax law"), Sebastian Heinrichs ("External tax effects and the subject tax principle"), Nicole Herrmann ("Tax subjects of the German Inheritance Tax Act") and Ruben Martini ("The personal scope of the Corporation tax"), inter alia, were awarded doctorates for their work on German Tax and Duties law (all books published in German).

Another core area is the Institute's research on European and International Tax Law. Together with Alexander Rust (Vienna), Ekkehart Reimer edits the internationally renowned DTC commentary “Klaus Vogel on Double Taxation Conventions”, is co-editor of the journal “Internationale SteuerRundschau” (ISR) and co-author of the renowned textbook “Europäisches Steuerrecht” (Schaumburg/English/Dobratz, 3rd ed. 2025). In the publication series “Heidelberger Beiträge zum Finanz- und Steuerrecht” (HFSt), which is edited by Hanno Kube and Ekkehart Reimer, “State aid law as a driver of innovation in tax law” (HFSt 8) was already a topic (published in German). In May 2023, the symposion of the Tax Law Research Association Heidelberg dealt with the topic of “Special taxes?”, including the EU excess profits tax.

Jakob Billau ("The tax integration of the European internal market through double taxation conventions"), Daniel Drescher ("The principle of equality of the European Charter of Fundamental Rights as applied to direct tax law"), Steffen Hörner ("The negative integration of national tax law systems"), Christian Jung ("The Multilateral Convention on the implementation of the BEPS project of the OECD and G20"), Lennart Neckenich ("State aid law in the system of competences"), Matthias Roth ("Group company as a permanent establishment"), Iris Schomäcker ("Constitutional tax law and legislative scope"), Noemi Strotkemper ("The tension between arbitration proceedings in tax matters and an international tax court") and Matthias Valta ("International tax law between efficiency, fairness and development aid"), inter alia, were awarded doctorates for their work on European and International Tax Law (all books published in German).

Hanno Kube and Ekkehart Reimer are members of the Arbeitskreis Steuergeschichte (Taxation History Working Group), which investigates the origins and effects of tax law norms. Several major Institute symposia were dedicated to taxation history topics – including in November 2021 under the title “The Tax Law of the Republic” on the 100th anniversary of Erzberger's fiscal reforms and in November 2024 on the topic of “100 Years of International Tax Law in Germany” on the occasion of a report by Herbert Dorn for the Deutscher Juristentag in 1924 on the avoidance of international double taxation. Christoph Bräunig also received his doctorate with the thesis “Herbert Dorn (1887-1957)” (published in German). Robert Pracht's habilitation project examines, among other things, the impact of the Reich Tax Procedure Code on general administrative law.

The Institute also has a particular focus on Public Budget and Debt Law. This is evidenced, among other things, by the relevant contributions by Hanno Kube and Ekkehart Reimer on Art. 109 et seq. GG in renowned commentaries on the German Basic Law. The debt brake enshrined in the Grundgesetz is a key point of academic interest.

In addition, Ekkehart Reimer delivered a report on the future structure of the federal fiscal order at the 73rd Staatsrechtslehrertagung in 2013 and, together with Simon Kempny (Bielefeld), prepared the report on the topic of “Reorganization of financial relations – task-oriented financial distribution between the federal, state and local governments” for the 70th Deutscher Juristentag in 2014. Ten years later, Hanno Kube delivered a report for the 74th Deutscher Juristentag 2024 on the topic of “Coping with future crises: What legal framework is needed to respond efficiently and effectively and distribute financial aid according to need?”. In addition, “Subsidiarity in the fiscal constitution” (HFSt 1) and “Lines of development in the fiscal constitution” (HFSt 3) have already been the subject of volumes in the publication series “Heidelberger Beiträge zum Finanz- und Steuerrecht” (HFSt) (all aforementioned projects published in German).

Since the euro crisis in 2010 at the latest, European Public Finance and Monetary Law has become considerably more important. In 2019, the Institute's symposion analyzed “Alternative Currencies: Challenges of Public Finance and Tax Law”, in 2020 it took place under the title “Solid Financing of the EU. Perspectives for the German Council Presidency”. In addition, the publication series “Heidelberger Beiträge zum Finanz- und Steuerrecht” (HFSt) regularly focuses on other EU public finance topics, such as “Legal bases and limits of the EU bank levy” (HFSt 2) and “European Public Finance Law: Current State – Methods – Perspectives” (HFSt 6) (both published in German). Sebastian Röger, for example, received his doctorate with the thesis “Financial aid mechanisms for the eurozone” (also in German).

Numerous specific legal problems lead to fundamental questions of law, its validity and interpretation. Members of the Institute have repeatedly presented work on constitutional theory and in particular (possible) constitutional prerequisites, but also on legal language, methodology, comparative law and the interdisciplinary connectivity of Public Law. Benjamin Straßburger completed his habilitation in 2020 with the thesis “Rule as a mandate. The notion of constitution of democratic constitutionalism and its significance for Germany's supranational integration”. Janis Beckedorf dealt with questions of the “Complexity of law” in his dissertation (both published in German).

As part of his membership in the 2020/21 Fellow Class of the Marsilius Kolleg, Hanno Kube worked on the project “Social self-empowerment: Extent, Reasons, Consequences, Measures”. He has also worked several times on the topic of “Trust in the constitutional state” and “Trust and loss of trust”. Matthias Valta completed his habilitation in 2016 with the thesis “State-related economic sanctions between sovereignty and human rights”.