Oral Mandate in Real Estate: The Court of Cassation Tightens the Rules of Evidence

Imagine the scene: you own a flat in Le Barcarès, overlooking the Mediterranean. One day, your spouse signs a preliminary contract of sale with a buyer, without telling you. You discover the matter when the buyer demands completion of the sale. Are you bound by this undertaking? The answer depends on a crucial question: did your spouse have a mandate (authority) to sell? And if that mandate was only oral, how can you prove it?

This is precisely the question decided by the Court of Cassation in a judgment of 19 December 1995 (No. 94-12.596). A decision which, nearly thirty years later, continues to set precedent throughout the south of France, from Perpignan to Argelès-sur-Mer.

In clear terms, the High Court recalls a fundamental principle: proof of a mandate, even an oral one, can only be adduced in accordance with the general rules on proof of agreements. In other words, if you want to prove that a person had the right to act on your behalf to sell your property, you must comply with the same requirements as for proving any contract. And these rules also apply in relations with third parties who dealt with the alleged agent (the person supposed to represent you).

The facts: a story that happens every day

The case begins in Argelès-sur-Mer, where a couple, Mr and Mrs Z..., own a property. One day, a preliminary contract of sale is signed by Mr Z... alone, to sell the property to a buyer, Mr Y... The problem? Mrs Z... did not sign the preliminary contract, and she does not want to sell. The buyer, however, insists: he claims that Mr Z... was acting as agent for his wife, and that this mandate, although oral, is valid. He therefore asks that the sale be completed (confirmed) and that ownership be transferred.

Mrs Z... contests: she never gave a mandate to her husband, and in any case, nothing is in writing. The Court of Appeal of Montpellier rules in her favour? Not quite. The trial judges consider that the mandate can be proved by any means, even in the absence of a written document. They hold that Mr Z... did indeed act on behalf of his wife, and order the sale.

Mrs Z... appeals to the Court of Cassation. She argues that proof of a mandate, even an oral one, must comply with the general rules of evidence. Now, for a transaction with a value exceeding €1,500 (at the time, 5,000 francs), written evidence is in principle required. A real estate sale far exceeds this threshold, so a written document was necessary. The Court of Cassation rules in her favour: it quashes the appeal judgment, on the ground that proof of a mandate can only be admitted in accordance with the general rules on proof of agreements.

The reasoning of the court — dissected

The reasoning of the Court of Cassation is a model of legal rigour. It first recalls the principle: proof of a mandate, even an oral one, is subject to the general rules on proof of agreements. Practically, this refers to Articles 1341 et seq. of the Civil Code (now Articles 1359 et seq.): for legal acts whose value exceeds a certain threshold (currently €1,500), written proof is mandatory. There are exceptions, such as a commencement of proof in writing or material or moral impossibility of obtaining a written document.

Next, the Court specifies that these rules also apply in relations between the principal (the one giving the mandate) and third parties who dealt with the alleged agent. In other words, the buyer cannot simply assert that the seller had an oral mandate: he must provide proof in accordance with general law. In this case, the Court of Appeal had admitted proof by any means, without verifying whether the conditions for the exceptions were met. That is an error of law.

What few people know is that this decision is not a revolution. It confirms consistent case law: a mandate is a contract like any other, and its proof must be adduced according to ordinary rules. undefined that for a mandate to sell a property, a written document is almost always necessary. Trial judges cannot rely on presumptions or witness statements alone, unless there is a commencement of proof in writing (a document from the principal that makes the existence of the mandate plausible).

However, be careful: the Court does not say that the oral mandate is void. It exists and can be valid, but proving it is difficult. In case of a dispute, it is the party relying on the mandate (the buyer or the agent) who must prove its existence, and this must be done by a written document or a commencement of proof in writing.

What this means for you — practically

For owners, this decision is a protection. If your spouse, your child or a friend signs a preliminary contract of sale for your property without your written consent, you are not obliged to sell. The buyer cannot force you, unless he proves in writing that you gave a mandate. undefined, I have come across cases where an owner in Perpignan had to face a claim for specific performance after his son had signed a preliminary contract. Thanks to this case law, the owner was able to invoke the absence of a written mandate and have the sale annulled.

For buyers, the message is clear: do not rely on mere words. If you deal with a person who presents himself as an agent (estate agent, spouse, etc.), demand a written mandate. Otherwise, you risk finding yourself in a difficult situation: you have signed a preliminary contract, you pay a deposit, and the owner refuses to sell. You might obtain damages if you prove the fault of the agent, but not forced sale.

Let us take a concrete example: in Argelès-sur-Mer, a 30 m² studio sells for around €120,000. If you sign a preliminary contract with the owner's son, who claims to have an oral mandate, and the owner refuses, you waste your time and costs (about €3,000 for surveys, agency fees, etc.). Without a written mandate, you cannot demand the sale. You can only claim damages from the son, if he acted without a mandate, but that is another procedure.

For real estate professionals (agents, notaries), this decision reminds them of the importance of verifying the powers of the signatory. An agent who accepts an oral mandate to sell a property takes a risk. If the owner contests, the agent could be sued for failure to verify. It is better to require a written mandate, even for a simple viewing.

Four tips to avoid this type of dispute

• Always require a written mandate for any real estate sale or purchase. Whether you are an owner or a buyer, do not settle for a verbal agreement. A written mandate, even a simple one (an email or a signed letter), protects you. For sales, the mandate must be express and specific (indicating the property, price, conditions).
• If you are a buyer and deal with an agent, ask to see the mandate. Check that it is signed by the owner, that it mentions the property and the price. Keep a copy. If in doubt, contact the owner directly to confirm.
• For couples, formalise mandates between spouses. If you wish your spouse to be able to sell a property belonging to you alone, establish a written mandate. Otherwise, in case of separation or disagreement, a preliminary contract signed by only one spouse can be contested.
• In case of a dispute, gather all written evidence. Even without a formal mandate, a commencement of proof in writing (email, text message, document) may suffice. For example, an email from the owner saying "My son is handling the sale" may be considered a commencement of proof. Keep everything.

Further analysis: related case law and developments

This 1995 decision is part of a consistent line of authority. Already, in a judgment of 15 December 1992 (No. 91-10.783), the Court of Cassation had ruled that proof of an oral mandate for a dispositionary act (such as a sale) can only be adduced in writing. More recently, in a judgment of 6 March 2013 (No. 11-27.287), it specified that the mandate can be tacit (implied), but its proof remains subject to the same rules. In other words, even a tacit mandate must be proved by writing or a commencement of proof in writing.

The trend is therefore towards strengthening the requirement for written proof, particularly for important real estate transactions. This protects owners against non-consensual commitments, but imposes increased vigilance on buyers and professionals. In the south of France, where transactions are numerous (especially in tourist areas like Le Barcarès or Argelès-sur-Mer), this case law is regularly invoked.

For the future, it is possible that case law may evolve towards a broader recognition of apparent authority (when the third party legitimately believed that the agent had the power to act). But for now, proof of the mandate itself remains strict.

Key points to remember

1. An oral mandate exists, but proving it is difficult. For a property, a written document is almost mandatory.
2. If you are an owner, you are not bound by a preliminary contract signed by a person without a written mandate. You can refuse the sale.
3. If you are a buyer, demand a written mandate before signing. Otherwise, you risk losing your deposit and not obtaining the sale.
4. In case of a dispute, a commencement of proof in writing can save your case. Gather all written documents.
5. Real estate professionals must verify the powers of the signatory. An oral mandate is a legal risk.

Are you in a similar situation? A 30-minute initial consultation with Maître Zakine (€45) can save you months of proceedings — and often much more. Book an appointment →