Art. 128 PILA from 2022

Art. 128 II. Applicable law
1 Claims for unjust enrichment are governed by the law which governs the existing or assumed legal relationship on the basis of which the enrichment occurred.
2 In the absence of such a relationship, the claims are governed by the law of the state in which the enrichment occurred; the parties may agree to the application of the law of the forum.
Es besteht kein Anspruch auf Aktualität und Vollständigkeit/Richtigkeit.