Short answer. No. Article 1647 of the Civil Code says that where a lease is to be recorded in the Registry of Property, a guardian cannot constitute the lease over the property of the minor or ward without proper authority. Registrable leases of a ward's land require special authority the guardian does not hold by default.
What the law says
the following persons cannot constitute the same without proper authority: the husband with respect to the wife's paraphernal real estate, the father or guardian as to the property of the minor or ward, and the manager without special power
Civil Code, Article 1647 — Authority Needed to Record Certain Leases. Read the full provision →
A registrable lease needs proper authority
The article singles out leases that are to be entered in the Registry of Property, the kind that will bind third parties and encumber the land on the public record. For those, it says certain persons cannot constitute the same without proper authority, and it names the father or guardian as to the property of the minor or ward among them. So a guardian's ordinary authority to look after a ward is not, by itself, enough to sign a lease of the ward's real estate that is meant to be recorded. That step requires the special or proper authority the law demands, which the guardian must actually obtain first.
Why registrable leases get extra protection
The heightened requirement reflects how much a recorded, long-term lease can affect a ward's property. Registration gives the lease durability and effect against others, and a lease of significant length can tie up the land and its income for years, well beyond simple day-to-day management. Because a minor or ward cannot protect his own interests, the law does not let a guardian burden the property with such a commitment on his own judgment alone. It inserts a control, the need for proper authority, so that this class of transaction receives the added scrutiny its impact warrants.
Ordinary administration is treated differently
The provision is aimed at leases to be recorded, which signals that not every arrangement over a ward's property is caught in the same net. Acts of simple administration that fall within a guardian's normal management stand on a different footing from constituting a registrable lease that encumbers the land on the public record. The line the article draws is around that recordable, more consequential category. A guardian should therefore be careful to identify when a proposed lease crosses into the territory that demands proper authority, rather than assuming his general role covers it.
What a guardian should do
A guardian who wants to grant a registrable lease of a ward's real estate should secure the proper authority the law requires before signing, through the channels that govern a ward's affairs, rather than proceeding on his own. Doing so protects both the ward and the lease: a lease constituted without the needed authority is exposed to challenge and may not hold, leaving the tenant and the ward in an uncertain position. The clean approach is to obtain the authorization first, keep proof of it, and only then constitute and register the lease.