TF, 18.06.2026, 2C_157/2024
Facts
The German Federal Central Tax Office submitted a request for administrative assistance to the Federal Tax Administration (FTA) regarding taxpayer A.________, based on the Double Taxation Convention between Switzerland and Germany (DTC CH-DE). The FTA decided to grant assistance via a final decision. (A., B.)
A.________ appealed this decision to the Federal Administrative Court (FAC), requesting, among other things, full and unredacted access to the file. He argued that one page of the assistance request was illegible and that certain documents had been partially blacked out. The FTA justified these redactions, which concerned the contact details of the requesting authority and the names of its staff, by citing the need to maintain good international relations. In an interlocutory decision, the FAC presiding judge granted the request for full access to the file, arguing that the requesting authority had consented to it and that the DTC CH-DE did not require such information to be kept secret. (B.a., B.b.)
The FTA then filed an appeal in public law matters with the Federal Supreme Court, requesting the annulment of the FAC's interlocutory decision insofar as it ordered the disclosure of the names and contact details of the requesting authority's staff. (C.)
Legal Analysis
The Federal Supreme Court first examines the admissibility of the appeal. This is an appeal against an interlocutory decision in a matter of administrative tax assistance. Admissibility is contingent upon the existence of a legal question of principle (art. 84a LTF) and irreparable harm (art. 93 para. 1 let. a LTF). The Federal Supreme Court acknowledges the existence of a question of principle, as the FTA maintains that developments in international practice and OECD commentaries since a 2015 precedent justify a re-examination of the confidentiality of foreign officials' data. Irreparable harm is also acknowledged, as once access to a file is granted, it cannot be reversed. (consid. 1.2, 1.3, 1.4)
The Federal Supreme Court reiterates the principles of interpreting international conventions, based on the Vienna Convention (art. 31 VCLT). Interpretation must be performed in good faith, in accordance with the ordinary meaning of the terms, in their context, and in light of the treaty's object and purpose. For double taxation conventions, the OECD Model Tax Convention (OECD Model) and its Commentary (OECD Comm.) are essential tools for interpretation. In principle, the Federal Supreme Court follows the most recent version of the Commentary, even if it postdates the convention, to ensure uniform and evolving application. However, this consideration has limits: a new interpretation cannot be adopted if it lacks a sufficient basis in the treaty text or is incompatible with mandatory domestic law standards, particularly fundamental rights. (consid. 4, 4.1, 4.2, 4.3, 4.4)
TheArt. 27(2) of the CH-DE DTA, which corresponds toArt. 26(2) of the OECD Model Tax Convention, establishes the principle of confidentiality for exchanged information. Such information may only be disclosed to specific persons or authorities involved in the tax procedure. According to legal doctrine and practice, the taxpayer concerned is among these persons, which forms the basis of their right to inspect the file. The Additional Protocol to the CH-DE DTA (ch. 3 let. f) specifies that the taxpayer's procedural rights under the domestic law of the requested State are reserved, with the aim of ensuring a fair procedure without hindering the effectiveness of the information exchange. (consid. 5.1, 5.2, 5.3, 5.4)
The right to inspect the file, which stems from the right to be heard (Art. 29(2) of the Federal Constitution), is not absolute. It may be restricted underArt. 27 of the Federal Act on Administrative Procedure (APA) in the presence of overriding public or private interests. Maintaining good international relations can constitute such a public interest. However, any restriction must result from a case-by-case balancing of interests and must respect the principle of proportionality. A restriction is only permissible if it is necessary to ensure the effectiveness of administrative assistance, for example, if disclosure would jeopardize cooperation. (consid. 6.1, 6.5, 6.5.1, 6.5.2, 6.5.3)
Application to the specific case
The FTA argues that the latest update to the OECD Commentary, which limits communication to the taxpayer to information "bearing on the outcome" of their tax procedure, requires the systematic redaction of the names and contact details of the requesting authority's agents. It cites a risk of international criticism and, therefore, a public interest in confidentiality. (consid. 3.1, 7.1)
The Federal Supreme Court rejects this argument. Firstly, it has not been demonstrated that the disclosure of these names and contact details would generally hinder the effectiveness of administrative assistance. The FTA does not allege that such a risk exists in this case. Secondly, the restrictive interpretation advocated by the FTA, based on the OECD Commentary, does not find sufficient support in the text of Art. 27 of the CH-DE DTA, the purpose of which is to protect the taxpayer rather than to withhold information from them. (consid. 7.2.1, 7.2.2)
Thirdly, such a generalized restriction would be contrary to the right to be heard (Art. 29(2) of the Federal Constitution), to which the CH-DE DTA explicitly refers. This constitutional right guarantees full access to the file, regardless of the relevance the authority assigns to a document. The decision as to what is relevant belongs to the individual. The FTA's interpretation, which is based solely on a possible but not mandatory reading of the OECD Commentary, does not constitute a sufficient public interest to justify a systematic derogation from a fundamental right. (consid. 7.2.3, 7.2.4, 7.2.5)
The Federal Supreme Court acknowledges that, under specific circumstances, confidentiality could be justified if the requesting authority demonstrated a risk of harm to its staff. In this case, the FTA has not cited any concrete circumstances of this nature, and the general situation in the requesting state (Germany) does not support the presumption of such a risk. On the contrary, the requesting authority even consented to the inspection of the file. (consid. 7.3)
In conclusion, neither the CH-DE DTA, nor domestic law, nor the specific circumstances justify a general obligation to redact the names and contact details of the requesting authority's agents. The conditions for a change in case law are therefore not met. (consid. 8)
Outcome
The Federal Supreme Court dismisses the appeal filed by the Federal Tax Administration. The interlocutory decision of the Federal Administrative Court, which grants A.________ unredacted access to the assistance request file, is upheld. (consid. 9, disp. 1)
No court costs are charged to the FTA. The FTA is ordered to pay legal fees to the respondent, A.________, for the federal proceedings. (disp. 2, 3)