(1) The effectiveness of a contract by which a descendant of the spouses agrees with one of the spouses to waive their share of the common matrimonial property of the continued community of property or by which such a waiver is revoked for the eventuality that the marriage is dissolved by the death of that spouse is subject to the approval of the other spouse. The approval is governed by the provision of section 1516 (2) sentences 3 and 4.
(2) The provisions applying to the waiver of an inheritance apply accordingly.