The Contract of Mandate (Contrato de Mandato) in Spain in 2026: CC Articles 1709-1739 and When a Property Agent Acts on Your Behalf

The contrato de mandato is the legal relationship under which one person (the mandatario) agrees to perform a service or act on behalf of another (the mandante) under Spanish civil law. Governed by Articles 1709 to 1739 of the Codigo Civil, it is the contractual backbone behind every gestor instruction, every apoderado acting before a Spanish authority, and every notarial power of attorney granted for a property transaction. Foreign property owners in Spain encounter this framework constantly, often without recognising it: the moment a gestor files your taxes, a lawyer signs on your behalf at the notary, or a relative manages your community fees while you are abroad, a mandate is in operation. Understanding its scope, the mandatary’s duties, and how it ends is essential to protecting your interests.

What is a contrato de mandato under Spanish law?

A contrato de mandato, defined in Article 1709 of the Codigo Civil, is a contract by which one person obliges themselves to perform a service or do something on account or by order of another. The relationship is bilateral once accepted: the mandatario owes duties of care and accounting, and the mandant owes duties of indemnification and reimbursement. The mandate may be express (granted by public or private instrument, or even verbally per Article 1710) or tacit, inferred from the mandatary’s conduct. It may be general, covering all the mandant’s affairs, or special, limited to one or more specific businesses (Article 1712).

The critical scope rule is Article 1713: a mandate conceived in general terms comprises only acts of administration. To transigir (settle), enajenar (dispose of property), hipotecar (mortgage) or carry out any other act of strict dominion, express authority is required. This means a general power of attorney does not authorise your representative to sell your Marbella apartment; the escritura de poder must specifically enumerate that faculty. The mandatary cannot exceed the mandate’s limits (Article 1714), though fulfilling it in a more advantageous manner for the mandant does not count as exceeding them (Article 1715).

Is a mandate in Spain presumed to be gratuitous or paid?

The default position under Article 1711 is that the mandate is presumed gratuitous unless the parties agree otherwise. However, if the mandatary practises the occupation or profession to which the mandated service belongs, the obligation to remunerate is presumed. A gestor who handles your tax filings is a professional providing a professional service, so the relationship is onerous by default. A friend who collects your post or checks on your property as a favour falls under the gratuitous presumption.

This distinction has a concrete liability consequence. Article 1726 provides that the mandatary is liable not only for dolos (fraud) but also for culpa (negligence), and courts assess the standard of care more or less rigorously depending on whether the mandate was remunerated. A paid gestor is held to a higher standard than a friend acting without compensation.

What duties does the mandatario owe the mandant?

The Codigo Civil imposes a demanding set of obligations on the mandatary, reflecting the fiduciary character of the relationship:

Duty	Article	Core requirement
Execute the mandate	1718	Bound on acceptance; liable for damages from non-performance
Follow instructions	1719	Act per mandant’s instructions; absent them, as a good paterfamilias
Render accounts	1720	Account for all operations and hand over everything received, even sums not owed to the mandant
Substitution liability	1721-1722	May appoint a substitute only if not prohibited; liable for the substitute’s acts in two cases
Personal liability	1725	Personally liable to third parties only if exceeding scope without informing them of the limits of their authority
Standard of care	1726	Liable for fraud and negligence; stricter for paid mandates
Interest on misapplied funds	1724	Owes interest on sums applied to personal use from the date of application

The account-rendering duty in Article 1720 is particularly important for property owners. A gestor managing your Spanish property must account for every euro received in virtue of the mandate, including sums that were not technically owed to you (for instance, a tenant’s overpayment). The mandatary who applies mandate funds to personal use owes interest from the day they did so (Article 1724).

When the mandatary acts in their own name rather than as representative, the mandant has no direct action against the third parties the mandatary contracted with, and vice versa (Article 1717). The mandatary is directly obliged to the third party as if the matter were personal, except when the subject concerns the mandant’s own property. This is a trap for foreign owners who instruct a local agent without verifying whether the agent is contracting in the owner’s name or in their own.

What happens if the mandatary exceeds the scope of the mandate?

Scope excess is one of the most practically significant issues for property owners. Article 1714 prohibits exceeding the mandate’s limits. When the mandatary does exceed them, Article 1727 provides the key rule: the mandant is not bound by acts outside the mandate unless they expressly or tacitly ratify them. Ratification retroactively cures the excess and makes the act fully binding.

Consider a common scenario. A Marbella property owner grants a mandate to a gestor to handle tax filings and community fees. The gestor, without express authority, signs a one-year residential lease on the owner’s apartment. Under Article 1713, leasing for more than six years is an act of strict dominion requiring express authority, not a mere administration act. The lease is not automatically binding on the owner. The owner’s remedies depend on whether they ratify the lease (accept it, accept rent from the tenant) or reject it. If they reject it, the gestor is personally liable to the tenant under Article 1725 for having exceeded scope without sufficiently informing the tenant of the limits of their authority.

The mandatary’s personal liability to third parties is also addressed in Article 1725. A mandatary acting as such is not personally liable to the party they contract with unless they expressly assumed personal liability or exceeded the mandate’s scope without giving sufficient notice of their powers. This means a properly authorised agent who stays within scope is shielded; the mandant, not the agent, is the party the third party must pursue.

What obligations does the mandant owe the mandatary?

The mandant’s obligations mirror the mandatary’s and complete the bilateral structure:

Obligation	Article	Core requirement
Honour mandatary’s contracts	1727	Fulfil all obligations the mandatary contracted within the mandate’s limits
Advance expenses	1728	If requested, advance sums necessary for execution; reimburse advances with interest
Indemnify losses	1729	Compensate the mandatary for damages caused by fulfilment without fault
Retention right	1730	The mandatary may retain the subject property in pledge until indemnified and reimbursed
Joint mandant liability	1731	Two or more mandants naming one mandatary for a common business are solidarily bound

The retention right in Article 1730 is a powerful tool. If a gestor advances EUR 2,000 in community fees and IBI payments on your behalf and you refuse to reimburse them, the gestor may retain your property documents or, in some circumstances, the subject of the mandate in pledge until you pay. This is a statutory lien, not a contractual invention.

How does the mandate end?

Article 1732 enumerates five causes that terminate a mandate:

1. Revocation by the mandant (Articles 1733-1735)
2. Renunciation by the mandatary (Articles 1736-1737)
3. Death or insolvency (concurso) of either the mandant or the mandatary
4. Establishment of support measures (medidas de apoyo) for the mandatary that affect the act in question, introduced by the Ley 8/2021 reform of capacity law
5. Constitution of representative curatela for the mandant, save for preventive mandates (mandatos preventivos)

The revocation rules are important for property owners. The mandant may revoke at will (Article 1733) and compel the return of the document evidencing the mandate. If the mandate was granted to contract with specific persons, revocation does not prejudice those third parties until they are notified (Article 1734). Appointing a new mandatary for the same business implicitly revokes the prior mandate from the day the original mandatary learns of it (Article 1735).

A mandatary may renounce (Article 1736) by notifying the mandant. If the renunciation causes damage, the mandatary must indemnify unless the renunciation was based on the impossibility of continuing without serious detriment to themselves. Even with just cause, the renouncing mandatary must continue managing until the mandant can make alternative arrangements (Article 1737).

Acts performed by a mandatary unaware of the mandant’s death or other terminating cause remain valid against third parties acting in good faith (Article 1738). The deceased mandatary’s heirs must notify the mandant and manage urgent matters in the interim (Article 1739).

How does the contrato de mandato differ from a notarial power of attorney?

The distinction between the contrato de mandato and a poder notarial (notarial power of attorney) confuses many foreign property owners. The mandato is the underlying legal relationship: one person agrees to act for another. The poder notarial is the formal instrument, granted before a notary, that evidences and enables the mandate for transactions requiring public faith. A mandate can exist without a notarial power of attorney (Article 1710 permits verbal or private mandates), but property transactions that require inscription in the Land Registry or execution before a notary demand a notarial poder.

The power of attorney for property in Spain is the standard vehicle for property mandates because the Land Registry and notaries require it. The Spanish notary’s role in a property purchase includes verifying the apoderado’s authority through the escritura de poder, and the public deed (escritura publica) explains why notarial instruments carry public faith that private mandates lack.

The gestor typically operates under a mandate that may or may not be formalised as a notarial power of attorney, depending on the tasks involved. Tax filings and community fee management can be done with a private authorisation; signing at a notary or registering property requires a notarial poder. When conducting a due diligence check before buying Spanish property, verifying the scope of any existing mandates granted to local representatives is a critical step that foreign buyers often overlook.

What is the practical risk of an unfettered mandate for a property owner?

The greatest practical danger for a non-resident property owner is granting a mandate with too broad a scope. A general power of attorney that empowers a representative to manage all your affairs in Spain sounds convenient, but Article 1713 limits a general mandate to administration acts. If the escritura de poder nonetheless enumerates express faculties to sell, mortgage or transact (as many do), the representative can dispose of your property without further consultation.

The protections are real but require vigilance. Article 1720’s account-rendering duty means the mandatary must report everything, but enforcement requires you to demand it. Article 1730’s retention right works in the mandatary’s favour, not yours. Article 1733’s revocation right is absolute, but only effective against third parties once they are notified (Article 1734). The lesson for foreign owners is to grant mandates that are as narrow as possible, to specify the exact acts authorised, to require periodic accounting, and to revoke promptly when the relationship changes.