The Federal Supreme Court upheld that decision and confirmed its existing case law: the double taxation agreement between Switzerland and Germany does not impose a general obligation to keep such information confidential from the person concerned by a request for administrative assistance. The right to be heard under Art. 29(2) of the Federal Constitution generally includes the right to inspect all documents created or obtained for the purposes of the proceedings, irrespective of whether the authority itself considers the information in question relevant to the decision.

The Federal Supreme Court attached particular importance to the relationship between international standards and constitutional procedural rights. While it generally takes account of the current version of the Commentary on the OECD Model Tax Convention when interpreting double taxation agreements, that Commentary cannot justify restrictions that have no sufficient basis in the treaty itself or that are incompatible with overriding constitutional rights.

Restrictions on access to the case file remain possible, but require specific interests worthy of protection in the individual case. This might be conceivable, for example, where employees of the requesting authority face a concrete threat or where disclosure would in fact impair the effective conduct of the administrative assistance proceedings. A general and context-independent redaction, by contrast, does not satisfy these requirements.

The decision strengthens the procedural rights of persons affected by requests for international administrative assistance in tax matters. Authorities cannot restrict access to the case file solely on the basis of general confidentiality interests or international administrative practice. Any restriction of the right to inspect the case file must instead have a basis in statute or treaty, be justified in the specific case and be proportionate.

By confirming its existing case law, the Federal Supreme Court makes clear that the scope of the rights to be heard and to inspect the case file in international administrative assistance proceedings is governed by the applicable treaty provisions. The Commentary on the OECD Model Tax Convention may assist in interpreting those provisions, but it cannot amend them or create restrictions on procedural rights for which the treaty itself provides no basis.

It is particularly welcome that the Federal Supreme Court also rejects the blanket withholding of information concerning the requesting authority and the persons involved in the request for administrative assistance. Such information may be material to the person concerned. In particular, it enables that person to verify whether the domestic procedures and rules on jurisdiction and competence in the requesting state have been complied with.

This may be of particular practical importance where there are indications that administrative assistance mechanisms are not being used exclusively for their intended purposes, but may instead serve to investigate persons or assets more broadly. A comprehensive right to inspect the case file provides an important procedural safeguard in such circumstances.

Source: Federal Supreme Court, judgment 2C_157/2024 of 18 June 2026.