Unjust Enrichment in Spain: When and How to Claim Your Money Back

🇪🇸 Read the original in Spanish

Have you ever felt that someone has financially benefited at your expense in a completely unjustified way, leaving you with a real financial loss? In the Spanish legal system, this situation is not left unprotected. It is addressed through a fundamental legal concept: enriquecimiento injusto (unjust enrichment) or enriquecimiento sin causa (enrichment without cause). Although it is not expressly regulated in detail in a single article of our Código Civil (Civil Code), it is a general principle of law consolidated by a century of jurisprudence from the Tribunal Supremo (Supreme Court). It is designed to restore the financial balance broken when one person enriches themselves at the expense of another's impoverishment without a contract, a law, or a just cause to legitimize it.

What is Unjust Enrichment and What is Its Legal Framework?

Unjust enrichment is a concept created by legal doctrine and case law, based on the principle that "no one should unjustly enrich themselves to the detriment of another." In Spanish civil law, its main objective is not to punish the person who gains, nor to award damages in the classic sense, but to restore the financial balance that has been unjustifiably broken.

Although the Spanish Código Civil does not contain a chapter exclusively dedicated to this concept, the jurisprudence of the Tribunal Supremo has derived it from the systematic interpretation of various provisions that reject enrichment without cause. Among them, the following stand out:

• *Article 10.9 of the Código Civil***: Which refers to obligations arising from enrichment without cause when determining the law applicable to these situations.
• *Article 1895 of the Código Civil (cobro de lo indebido / collection of what is not owed)*: Which establishes that when something is received that there was no right to collect, and which had been delivered by mistake, the obligation to restore it arises. This is the clearest example of this principle being written into positive law.
• *Article 1901 of the Código Civil***: Which presumes that there was an error in payment when something was delivered that was never owed or was already paid.

For Spanish courts (under the rules of the Ley de Enjuiciamiento Civil 1/2000 or Civil Procedure Act) to accept a lawsuit for unjust enrichment, jurisprudence strictly requires the coexistence of five cumulative requirements. If even one of them is missing, the claim will be dismissed.

The 5 Mandatory Requirements to Make a Claim

For judicial actions of unjust enrichment to succeed, the plaintiff must prove to the civil judge the existence of the following elements:

1. An enrichment of the defendant

There must be an increase in the defendant's assets. This enrichment can be positive (an increase in assets, such as receiving money, property, or a free service) or negative (a saving of expenses, meaning avoiding an outlay that they were legally responsible for making).

2. An impoverishment of the plaintiff

There must be a correlative financial loss in the claimant's assets. This impoverishment can consist of a transfer of assets, the loss of a legitimate lucro cesante (loss of profit), or the performance of work or services that have not been paid for.

3. Causal relationship (causal link)

There must be a direct link between the impoverishment of one party and the enrichment of the other. The benefit of the defendant must come directly from the financial sacrifice of the plaintiff.

4. Lack of justifying cause

This is the core of the claim. It must be proven that there is no legal reason to justify the transfer of assets. There must be no valid contract between the parties, no legal provision, and no donation (ánimo de liberalidad / intent of generosity) that supports one party keeping the benefit at the expense of the other.

5. Subsidiary nature of the action

The jurisprudence of the Tribunal Supremo has established that the action for unjust enrichment is subsidiary in most scenarios. This means that you cannot resort to it if you have another specific legal action available to claim (for example, an action for contractual liability, non-contractual liability, or rescission). It can only be exercised when no other legal avenue exists to repair the damage.

Practical Examples with Real Figures

To understand how this concept works on a day-to-day basis, we analyze two common scenarios in Spanish courts:

Example 1: Duplicate payment due to administrative error

Let's imagine that Carlos owns a commercial premises and has hired a renovation company to refurbish the space. The work is budgeted at €15,000. Due to an error by his accounting department, two identical bank transfers of €15,000 each are issued in the same month, totaling €30,000 received by the construction company.

The renovation company notices the error but decides to ignore Carlos's emails and does not return the excess money. In this case:

• There is an enrichment of the construction company (€15,000 extra).
• There is an impoverishment of Carlos (€15,000 less).
• There is a direct causal link.
• There is no cause (the construction contract only covered the payment of €15,000).
• Carlos can legally claim the return of the €15,000 based on cobro de lo indebido and unjust enrichment.

Example 2: Renovations on someone else's property before a breakup

María and Juan live together in a home owned exclusively by Juan. They decide to carry out a complete renovation of the kitchen and bathroom to improve liveability. María finances the works entirely out of her own pocket, spending a total of €12,000 on materials and labor, expecting to enjoy the home in the long term. Three months after the works are completed, the relationship breaks down and Juan demands that María leave the property.

• Juan has enriched himself: his home is now worth more or has better qualities thanks to a renovation he did not pay for (a saving of €12,000).
• María has been impoverished by €12,000.
• There is no rental or construction contract between them that justifies María giving this improvement to Juan as a gift.
• María can file an unjust enrichment lawsuit to claim compensation from Juan for the €12,000 (or the increase in the property's value).

Practical Steps: How to Claim Step-by-Step

If you find yourself in a situation of financial imbalance and decide to claim, you must follow an orderly legal strategy to ensure the success of your claim:

``` [Step 1: Gathering Evidence] │ ▼ [Step 2: Out-of-Court Claim (Burofax)] │ ▼ [Step 3: Attempted Mediation or Conciliation] │ ▼ [Step 4: Lawsuit (LEC)] ```

Step 1: Exhaustive gathering of evidence

Before starting any action, you must gather all documents that prove the transfer of value. This includes:

• Bank statements, proof of transfers, and receipts.
• Invoices for the purchase of materials or services rendered.
• WhatsApp messages, emails, or letters showing that the defendant acknowledges receipt of the money or service, or proving the lack of intent to donate.
• Expert reports (essential if claiming the increase in value of a property or asset).

Step 2: Prior out-of-court claim

It is highly recommended to send a formal claim before going to court. The ideal method in Spain is the Burofax with acknowledgement of receipt and certified text. This document must detail clearly:

• The origin of the error or the financial transfer.
• The exact amount claimed (for example, €3,500).
• A reasonable deadline for return (usually 10 or 15 business days).
• The express warning of initiating civil legal actions if no response is received.

Step 3: Attempted mediation or conciliation act (Optional but recommended)

If the burofax has no effect, you can file a papeleta de conciliación (conciliation petition) before the Juzgado de Paz (Justice of the Peace) or the Juzgado de Primera Instancia (Court of First Instance) of the defendant's domicile. This is a quick and inexpensive procedure that seeks to have the defendant acknowledge the debt and reach a payment agreement without the need for a formal trial.

Step 4: Filing the civil lawsuit

If the friendly route fails, a civil lawsuit must be filed before the Juzgados de Primera Instancia. Depending on the amount claimed, the procedure will vary according to the Ley de Enjuiciamiento Civil (LEC):

• **Juicio Verbal (Verbal Trial): For claims up to €15,000. It is a faster procedure. If the amount is less than €2,000*, it is not mandatory to appear with a lawyer or procurador* (court representative), although it is always advisable.
• **Juicio Ordinario (Ordinary Trial): For claims exceeding €15,000* or when the matter is particularly complex. Here, the intervention of a lawyer and procurador* is always mandatory.

Deadlines, Amounts, and Key Figures You Must Know

Time is a critical factor in Spanish civil law. You cannot claim indefinitely. These are the key figures and deadlines you must keep in mind:

• 5-year statute of limitations: Following the reform of the Código Civil, the general term to exercise personal actions that do not have a special term (such as the action for unjust enrichment) is 5 years, as established by *Article 1964.2 of the Código Civil***. The period begins to run from the moment the fulfillment of the obligation could be demanded (when the enrichment without cause is consolidated).
• €2,000 limit to litigate for free: If the amount you are going to claim is equal to or less than €2,000, you can file the lawsuit yourself using the court's standard forms, without the need to pay lawyer or procurador fees.
• Late payment interest: When claiming the amount, you have the right to request the legal interest on money from the date of the judicial claim (or from the out-of-court claim if the recipient's bad faith is proven).

Common Mistakes to Avoid When Claiming

Initiating a claim of this type without proper preparation can lead to losing the lawsuit and being ordered to pay court costs (condena en costas), which means paying the other party's lawyers. Avoid these mistakes:

• Confusing unjust enrichment with a breach of contract: If there is a signed contract between the parties, you cannot use the action for unjust enrichment. You must sue for "breach of contract" (Article 1124 of the Código Civil). Unjust enrichment only applies if the contract is null and void or if the benefit completely exceeds what was agreed in it.
• Not being able to prove your own impoverishment: It is not enough to show that the other person has gained money in a suspicious or unethical way; you must prove that this money or benefit came directly from your assets or your personal effort.
• Claiming when there was an intent to gift (generosity): If you gave a car to your partner or made voluntary transfers without expecting anything in return during the relationship, you cannot claim unjust enrichment after the breakup. The law understands that there was an ánimo de liberalidad (intent of donation), which constitutes a just cause that legitimizes the other person's enrichment.
• Letting the 5-year deadline pass: If you let time pass due to laziness or informal negotiations without sending a burofax to interrupt the statute of limitations, you will permanently lose the right to claim in court.

Frequently Asked Questions (FAQ)

Can I claim if I paid someone else's debt by mistake?

Yes. The Código Civil specifically regulates payment by a third party. If you pay someone else's debt without them knowing or against their express will, you can claim reimbursement for whatever part of the payment was useful to them (Article 1158 of the Código Civil). This is a direct application of the principle of unjust enrichment, as the debtor has been freed from a financial burden at your expense.

If my ex-partner stayed living in the apartment I pay for, is there unjust enrichment?

It depends on the circumstances and whether there is a court ruling on divorce or child custody measures. If a judge assigned the use of the home to your ex-partner to protect minor children, there is a legal cause (the court ruling), so there is no unjust enrichment. However, if there are no children or ruling, and you continue to pay 100% of the mortgage on a flat that belongs to both of you while only one enjoys it, you could claim exclusive use or compensation for the administration of common property.

What happens if the enriched person acted in good faith and no longer has the money?

Good faith does not exempt someone from the obligation to restore unjust enrichment. The difference lies in the scope of the return. If the person acted in good faith (they did not know the money did not belong to them), they are only obliged to return the item or the amount equivalent to the enrichment they still retain. If they acted in bad faith (knowing perfectly well it was an error), they must return not only the original amount but also the accrued interest and answer for any possible damages caused.

Can this concept be applied in the workplace?

Yes, very commonly. This happens when an employee performs duties of a higher professional category than the one recognized in their contract without receiving the salary corresponding to that higher category. Since there is no cause to justify the company benefiting from skilled work while paying less, the labor courts award salary differences based on the unjust enrichment of the company.

Summary

• Unjust enrichment requires a direct and correlative financial imbalance between two people (one gains and another loses).
• It is an indispensable requirement that there is no valid contract, law, or donation to justify this financial transfer.
• The action is strictly subsidiary and must be exercised within a maximum period of 5 years.
• For claims under €2,000, it is not mandatory to hire a lawyer or procurador, although it is highly recommended to structure the evidence.
• The courts reject the claim if it is proven that the initial impoverishment was due to an act of mere generosity (a gift) or the exclusive negligence of the claimant.

General legal information, not personalised legal advice. For your specific situation, ask your question for free at AbogadoAI — answers grounded in Spanish law (BOE), in English.

This is general information, not legal advice. Verify on the BOE or consult a lawyer for your specific case.