Short answer. Yes, but not alone. The Family Code makes it indispensable for the court-appointed guardian to be made a party to the marriage settlement whenever the person signing it is under a sentence of civil interdiction or another disability. Without the guardian joining, the settlement is not validly executed.
What the law says
For the validity of any marriage settlement executed by a person upon whom a sentence of civil interdiction has been pronounced or who is subject to any other disability, it shall be indispensable for the guardian appointed by a competent court to be made a party thereto.
Family Code, Article 79 — Marriage Settlements by a Person Under Civil Interdiction or Disability. Read the full provision →
The extra requirement this article adds
Article 79 addresses marriage settlements executed by a person on whom a sentence of civil interdiction has been pronounced, or who is subject to any other disability. For such a person, the article makes one thing indispensable for the settlement to be valid: the guardian appointed by a competent court must be made a party to it. This sits on top of the ordinary requirements for a marriage settlement — writing, signature, and execution before the marriage — as an additional condition tied specifically to the person's disability.
Why the guardian's participation is required
Civil interdiction and other disabilities affect a person's capacity to manage their own affairs, which is exactly what a marriage settlement governs. Article 79 responds to that by requiring the guardian appointed by the court — not just any relative or representative — to join the settlement as a party. The article calls this indispensable, meaning it is not treated as optional or curable by informal consent; the guardian's participation is a condition of the settlement's validity itself.
What "party thereto" means for the document
Because the guardian must be made a party to the settlement, the guardian's involvement has to appear in the settlement document, alongside the person under interdiction or disability and their intended spouse. The article does not spell out the guardian's specific role or powers within the settlement beyond requiring their participation as a party; it establishes the requirement rather than detailing every consequence of the guardian's presence.
Who the guardian must be
The article is specific that the guardian must be one appointed by a competent court. A guardian chosen informally by the family, without a court appointment, does not satisfy what Article 79 requires. If you or someone you are marrying is under a sentence of civil interdiction or another disability, confirming that a court-appointed guardian exists and is joined to the settlement is a threshold step before the document can be treated as validly executed.