Unpaid Additional Works: When Written Instructions Are Mandatory (Cass. civ. 1974)

Imagine: you are the owner of a property in Trélazé, you have signed a shell construction contract to build your house. During the works, the contractor tells you that an additional concrete slab is needed, not originally planned. You agree verbally, he pours it, and then you receive an invoice for €15,000 which you refuse to pay. The conflict begins. Who is right? The answer lies in one word: writing.

This question is asked by hundreds of owners and contractors each year. Is a written instruction required for additional work to be payable? The Court of Cassation, in a decision of 8 October 1974, ruled: yes, if the contract so provides, even if this seems strict. Let us dissect this decision which, fifty years later, remains a reference.

The case pitted a contractor against a client in Angers. The shell construction contract contained a clause: the contractor must immediately carry out written instructions for unforeseen works. The Angers Court of Appeal ruled in favour of the client, refusing payment for additional work without written instructions. The Court of Cassation confirmed. Do you want to understand why and how to protect yourself? Read on.

The facts: a story that happens every day

In 1968, Mr. Dupont (fictitious name), owner in Trélazé, entrusted the entire shell construction of a residential building to the company Bâtir. The contract, a fixed-price contract, provided in Article 13 that "when it is deemed necessary to carry out unforeseen works, the contractor shall immediately comply with the written instructions he receives to this effect." Work began, but soon unexpected issues arose: deeper foundations were needed, load-bearing walls needed reinforcement. The contractor, to avoid delaying the project, carried out this work without written instructions from the client. He thought he was doing the right thing: the client was on site, saw the work, said nothing, sometimes even verbally agreed.

At the end of the project, the contractor submitted an additional invoice of 120,000 francs (approximately €18,300 today). The client refused to pay: "You have no written instruction, I owe nothing." The contractor sued the client before the Tribunal de Grande Instance of Angers. At first instance, the court partly ruled in his favour, considering that the work was necessary and that the lack of writing was not an obstacle. But the client appealed.

The Angers Court of Appeal, in a judgment of 6 June 1973, overturned this decision. It held that the contractual clause was clear: written instruction is a mandatory condition. Without it, the contractor cannot claim any additional payment. The contractor appealed to the Court of Cassation. He argued that this clause could not require writing for unforeseen and necessary work, as that would distort its meaning. But the Court of Cassation dismissed his appeal on 8 October 1974, upholding the Court of Appeal's decision. The high judges affirmed that the Court of Appeal had not distorted the clause by requiring a written instruction. End of story: the contractor will not be paid for the unwritten work.

The court's reasoning — dissected

To understand this decision, one must first grasp the principle in contract law: the binding force of contracts. Article 1103 of the Civil Code (former Article 1134) provides that "legally formed agreements take the place of law for those who have made them." Here, the contractual clause was clear: written instruction is mandatory for additional work. The Court of Cassation therefore checked whether the Court of Appeal had distorted this clause, i.e., whether it had given it a meaning contrary to its terms.

The contractor argued that the clause should be interpreted as a mere option for the client to give written instructions, but that the absence of writing did not prevent payment if the work was necessary. However, the Court of Appeal, and the Court of Cassation following it, considered that the terms "shall immediately comply with the written instructions" are clear and precise: the contractor is obliged to wait for a written instruction before carrying out additional work. If he does not, he acts at his own risk.

The reasoning is also based on the principle of freedom of contract: the parties freely accepted this clause, and they must respect it. The Court of Cassation did not rule on the merits (was the work necessary?), but only on the interpretation of the clause. This is a review of the legal characterisation of the facts, not a re-examination of the dispute. In other words, the Court said: "The clause is clear, the Court of Appeal applied it correctly, no need to go further."

This decision is neither an evolution nor a reversal: it confirms a consistent line of case law since the 19th century on the binding force of contractual clauses. It reminds us that, in French law, the letter of the contract prevails, especially when it is precise. Judges cannot "rewrite" the contract to correct a potential injustice. If the contractor wanted to protect himself, he should have negotiated a different clause or required a written instruction before intervening.

What this means for you — practically

This decision has very concrete implications for all construction stakeholders. For a landlord owner in Angers, it is a protection: you do not have to pay for work you did not order in writing. But be careful: if you are on site and verbally encourage the contractor, you could be deemed to have implicitly accepted. To avoid any risk, always require a written instruction, even for a small modification.

For a contractor, it is a trap to avoid. Never rely on a verbal agreement. Even if the client says "it's fine, do it," ask for an email, a letter, or better, a written instruction. Otherwise, you risk working for free. Imagine: you carry out €8,000 worth of additional work on a site in Trélazé. Without a written instruction, you cannot claim it, even if the client benefited from it.

For a buyer of real estate, this case law is useful when taking over the works. Check that all additional items were authorised in writing. If a contractor claims payment for unwritten work, you can refuse. For a co-owner, it is the same: if the managing agent orders additional work without written authorisation from the general meeting, you could challenge the invoice.

A concrete example: in Angers, an individual has an extension built. The contractor adds soundproofing not originally planned for €6,000, based on a simple verbal request from the owner. The owner subsequently refuses to pay. Without a written instruction, the contractor loses his money. If you are in this situation, you must immediately stop any unwritten work and ask for a signed document. The time limit for legal action is 5 years (standard limitation period), but the longer you wait, the harder it is to prove.

Four tips to avoid this type of dispute

• Require a written instruction before any additional work: Whether you are the client or contractor, never start work outside the contract without a signed document. A simple email with read receipt may suffice, but a paper instruction is stronger.
• Draft a clear clause in your contract: If you are a contractor, propose a clause that provides that additional work must be ordered in writing, but also that it will be paid based on a prior estimate. If you are an owner, ensure the clause requires prior writing.
• Keep a record of all communications: Save emails, letters, and site photos. In case of a dispute, these elements can prove that the client was aware and accepted the work, even without a formal written instruction.
• If there is a disagreement, stop the work: If the client refuses to sign a written instruction, do not continue. Send a formal notice by registered letter asking him to confirm his request. This protects your rights.

Further reading: related case law and developments

This 1974 decision is part of a line of rulings that protect the client against unauthorised additional work. For example, the Court of Cassation ruled in a decision of 13 January 1993 (No. 90-21.756) that the absence of a written instruction prevents payment for additional work, even if it was essential to complete the project. Similarly, the decision of 12 July 2000 (No. 98-16.459) specifies that the contractor cannot invoke unjust enrichment to circumvent the lack of writing, because he was at fault for not requiring an instruction.

The trend of the courts is therefore consistent: contractual formality is strict. However, since the reform of contract law in 2016, judges can sometimes temper the strictness of clauses by invoking good faith (Article 1104 of the Civil Code). But in the case of additional work, the Court of Cassation remains firm. In the future, judges may more easily accept electronic evidence (such as SMS), but the principle of writing remains central.

Checklist before acting

• Do I have a written contract that sets out the procedure for additional work? Check the clause: does it require a written instruction? If so, follow it to the letter.
• Did I request a written instruction for each additional item? If not, stop the work and require a written instruction before continuing.
• Can I prove that the client verbally accepted the work? Gather evidence: witness statements, emails, photos. But be aware that this does not replace a contractual writing.
• What is the amount of the dispute? If less than €5,000, try mediation before going to court. If more, consult a lawyer specialising in property law.
• What is the time limit for action? 5 years from the invoice or completion of work. Do not delay.

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 →