Swiss Federal Supreme Court, 27.09.2025, 9C_113/2025
Facts
A taxpayer (the appellant) was named as a beneficiary for 50% of the deceased's estate, amounting to CHF 1,936,480. The Lucerne cantonal tax authority applied the maximum tax rate of 40% (a base tax of 20% plus a 100% progression surcharge), which is the rate for non-relatives, resulting in a tax bill of CHF 774,592.
The appellant claims to be the biological nephew of the deceased, asserting he is the natural son of her late brother, a Catholic priest. He provided DNA evidence and witness testimony supporting a high probability of this biological relationship. If recognized as a nephew, the tax rate would be 12%.
However, the appellant has no legally established filiation with his alleged biological father. A paternity suit was definitively dismissed by the Zurich civil courts because it was filed too late under the transitional provisions of the Civil Code (Art. 13a Final Title CC). The Lucerne Cantonal Court upheld the 40% tax rate, ruling that only a relationship formally recognized under civil law is relevant for tax purposes.
Legal Analysis
The dispute concerns the interpretation of the Lucerne Inheritance Tax Act (EStG/LU), specifically Section 3. This provision, which falls under non-harmonized cantonal law, sets tax rates based on the degree of kinship to the deceased.
Section 3(1) EStG/LU (the base provision) sets a rate of 6% for the "parental line" (second parentela, including nephews and nieces) and 20% for non-relatives or distant relatives. In principle, the interpretation of tax law concepts aligns with those of civil law (the principle of civil law authority). Under the Civil Code, kinship arises from a legally established filiation (by birth, recognition, or court judgment), not merely from a biological link.
However, Section 3(2) EStG/LU (the supplementary provision) extends the application of preferential rates to "blood relatives born out of wedlock, provided they have the status of an heir" ("uneheliche Blutsverwandte, sofern dieselben erbberechtigt sind"). This provision is an autonomous creation of Lucerne cantonal law that has no equivalent in federal inheritance law.
Application to the Case
The Federal Supreme Court examines the case in two stages.
First, it analyzes the application of the base provision (Section 3(1)(a) EStG/LU). It upholds the Cantonal Court's approach that the concept of "parental line" must be interpreted in accordance with civil law. In the absence of a legally recognized filiation, the appellant cannot directly benefit from the preferential rate provided by this section. This interpretation is not considered arbitrary.
Second, and this is the decisive point, the Federal Supreme Court finds that the lower court completely failed to examine the supplementary provision (Section 3(2) EStG/LU). The specific purpose of this provision is to mitigate the harshness of a purely formal approach by extending preferential rates to blood relatives born out of wedlock.
For this provision to apply, two conditions must be met:
- The existence of a blood relationship ("Blutsverwandtschaft").
- The status of an heir ("erbberechtigt").
The cantonal court should have examined these two conditions. It should have, as a preliminary matter, evaluated the evidence of biological filiation (DNA testing, testimony) and, if necessary, ordered a judicial expert opinion. It should also have interpreted the cantonal concept of "status of an heir" to determine whether it refers only to legal heirs or if it also includes heirs appointed by will, as is the case for the appellant. By completely ignoring this legal provision, the lower court committed an error of law.
Outcome
The Federal Supreme Court allows the appeal and sets aside the judgment of the Lucerne Cantonal Court.
Finding that the relevant facts (blood relationship) and the interpretation of a key part of cantonal law were not examined, the Federal Supreme Court cannot rule on the merits itself. To avoid depriving the appellant of a level of jurisdiction, it refers the case not to the cantonal court, but directly to the first-instance authority (the municipality of U.________) for a new investigation and decision. The latter must examine whether the conditions for applying § 3 para. 2 EStG/LU are met.
Silex Tax Newsletter published in collaboration with Anna Vladau, Attorney at Law
