1. Whoever receives, by way of performance, what is undue to them shall be bound to make restitution thereof if it remains in existence, or to restore its equivalent or its value if it is no longer in existence. 2. No restitution shall be due if the person who made the performance knew that they were paying what was not due, unless they were of limited legal capacity or were coerced into this performance.
Interpretation and application must be checked against the official text and current version.