The art of complaining: explanation of the duty to complain

The duty to complain (Article 6:89 of the Dutch Civil Code) requires you to complain within a reasonable time after you have discovered — or ought to have discovered — a defect in performance. If you fail to do so, you may lose your right to hold the other party liable, even if the defect actually exists. There is no fixed time limit; it depends on the circumstances. Below, you can read what the duty to complain entails, how quickly you must complain, and what a complaint must look like.

What is the duty to complain?

The duty to complain is set out in Article 6:89 of the Dutch Civil Code and obliges a creditor to report a defect in performance to the debtor within a reasonable period. This duty protects the debtor against late and difficult-to-refute complaints: the longer you wait, the more difficult it becomes for the other party to investigate what happened and to defend themselves.

The penalty is severe. If you complain too late, you may lose your right to hold the debtor liable. The judge then often does not even address the substance of the defects, but dismisses the claim based on the duty to complain.

Within what timeframe must you file a complaint?

The complaint period begins to run as soon as you have discovered the defect or should reasonably have discovered it. There is no fixed period — what is “reasonable” depends on the circumstances, such as:

• the nature and observability of the defect;
• the complexity of the performance;
• the expertise of the parties involved;
• or whether the debtor has been disadvantaged by the long wait.

That waiting too long can be your undoing is evident from a case in which a landlord only complained about tens of thousands of euros in rental damages after two years . The judge found that to be far too late. The practical lesson: investigate quickly if in doubt, and complain sooner rather than later.

Pay attention to the contractual duty to complain

Sometimes a contract or the general terms and conditions specific agreements regarding the duty to complain, for example, a concrete period of fourteen days. Such a contractual duty to complain creates clarity and prevents disputes regarding the open statutory standard. Therefore, always take into account what is stated in the contract or the terms and conditions — that period may be shorter and stricter than the statutory one.

What should a complaint look like?

The complaint is not subject to any formal requirements, but must be sufficiently clear. “The performance is unsatisfactory” is too vague: the debtor cannot do anything with that. A good complaint contains:

• The nature of the defect: what exactly is wrong?
• The extent: how serious and how significant is the deficiency?
• what you expect: repair, replacement, or compensation.

Preferably send the complaint in writing and keep proof of sending, so that you can later prove that (and when) you complained.

Why the duty to complain is important for entrepreneurs

• Legal certainty: a timely complaint enables the other party to investigate and remedy the defect; if no complaint is made, you may assume that everything is in order.
• Preservation of your rights: only by filing a timely complaint can you claim rectification or compensation .
• Preventive effect: complaining early encourages a quick solution and prevents long, costly procedures.

Frequently asked questions about the duty to complain

Does the duty to complain also apply between entrepreneurs?

Yes. The duty to complain applies broadly to agreements. In B2B relationships, professional vigilance is often expected, which means the reasonable complaint period can be relatively short. Additionally, pay attention to any contractual complaint period.

What is the difference compared to prescription?

The duty to complain concerns how soon you must complain after discovery; the statute of limitations concerns the maximum period within which you can file a claim. Both can terminate your right, but they are separate thresholds — you must meet both.

I received a (late) complaint myself. Can I dismiss it?

Possibly. If the customer complained too late and you have been disadvantaged as a result, you can invoke the duty to complain. Whether that succeeds depends on the circumstances. Have the situation assessed before you respond.

Assistance with the duty to complain

The legal experts at MKB Juristen advise on whether a defect could reasonably have been discovered and what constitutes a reasonable complaint period. We draft your complaint letter, provide advice if you receive a complaint yourself, and assist you in negotiations or, if necessary, in legal proceedings. Schedule a no-obligation intake.