Short answer. No. Article 1939 of the Civil Code makes commodatum strictly personal: the bailee cannot lend or lease the borrowed property to a third person. Members of the bailee's household may use it unless the contract says otherwise or the nature of the thing forbids it, but outsiders beyond the household are excluded.
What the law says
Commodatum is purely personal in character. Consequently: (1) The death of either the bailor or the bailee extinguishes the contract; (2) The bailee can neither lend nor lease the object of the contract to a third person. However, the members of the bailee's household may make use of the thing loaned, unless there is a stipulation to the contrary, or unless the nature of the thing forbids such use.
Civil Code, Article 1939 — Commodatum Is Personal. Read the full provision →
Why commodatum is personal
Article 1939 opens with the governing principle: "Commodatum is purely personal in character." The word purely is not decorative. Commodatum is a gratuitous loan for use — the bailor lends without charge, trusting a specific person to use and return the thing. That trust is the foundation of the contract. The bailor chose you, not anyone else, to use the property. The personal character of the arrangement means it cannot be delegated, assigned, or extended to third parties without defeating the very basis on which the loan was made.
The prohibition on lending or leasing to others
The personal nature of commodatum produces a concrete prohibition: "The bailee can neither lend nor lease the object of the contract to a third person." You cannot sub-lend the borrowed item to a friend, a relative outside your household, or anyone else. You cannot lease it to a third party and collect rent from it. Doing either would exceed your rights as bailee and breach the contract. If you allow a third person to use the borrowed property without the bailor's consent, you bear responsibility for any damage or loss that results, even if it would otherwise have been considered fortuitous.
Household members are the exception
The statute carves out one exception: "the members of the bailee's household may make use of the thing loaned." This recognizes that a borrowed item used within the home — a borrowed appliance, vehicle, or tool used by a spouse or child who lives with the bailee — is still effectively in the bailee's custody and control. The bailor can reasonably be said to have contemplated this kind of incidental household use. But two conditions can remove even this exception: a stipulation in the contract that excludes household members, or the nature of the thing itself, which may be so personal or specialized that household use is inappropriate.
What happens if you allow unauthorized use
Allowing a third person outside your household to use borrowed property exposes you to liability that goes beyond an ordinary breach. Under the Civil Code's provisions on commodatum, a bailee who violates the personal nature of the contract by allowing unauthorized third-party use takes on responsibility for the thing even in cases of fortuitous events that would otherwise excuse the bailee. In practical terms: if the borrowed car is damaged or stolen while in the hands of an unauthorized third party, you will likely bear the loss even if the damage or loss was not your fault. The bailor entrusted the property to you personally — keeping it in your custody is not optional.