Administrative assistance and professional secrecy of lawyers: who has the final say?

The taxpayer is a French tax resident, a lawyer practising in France and also registered as an EU/EEA lawyer in a cantonal register in Switzerland.
Firstly, France requests judicial assistance from Switzerland, which is granted.
2️⃣ Secondly, France requests administrative assistance from Switzerland for different accounts in Switzerland held at four different banks.
3️⃣ In a third step, taxpayers file a request for regularisation in France but refuse to communicate various details to the French tax authorities.
4️⃣ Fourthly, the French tax authorities again request administrative assistance from Switzerland, as taxpayers refuse to provide them with certain explanations.

The taxpayers (the lawyer and their spouse) object to administrative assistance due to professional secrecy. The AFC validates the administrative assistance. Regarding professional secrecy, the AFC indicated that the documents came from the banks and not from the lawyer themselves, so professional secrecy could not be invoked.

Federal judges note that the LAAF is silent on the matter. The lawyer is considered an interested party within the meaning of the LAAF. He may assert his rights. The CDI-F also allows for the non-transmission of documents covered by professional secrecy. Professional secrecy extends beyond the lawyer alone and is of public interest. Federal judges further refer to the ECHR to underline this public interest. Federal judges order that all names indicated on client account statements must be redacted.

The ruling is in French. An ATF publication is planned.

Federal Tribunal, judgment 2C_116/2023, of 2 May 2025