How to write a letter of formal notice in Switzerland

An unpaid invoice, a tradesperson who does not finish the work, a deposit that is never refunded: before starting debt enforcement or legal action, the formal notice (mise en demeure) is the basic first step. It formally informs your debtor that you demand performance, and it has concrete legal effects under the Swiss Code of Obligations (CO), articles 102 et seq.

Under art. 102 al. 1 CO, the debtor of an obligation that is due is placed in default by the creditor's demand. As long as you have not claimed anything, a mere delay is in principle not enough. There is, however, an important exception: when the day of performance was fixed by mutual agreement, for example a specific due date on the invoice or in the contract, the debtor is in default as soon as that day has passed, without any further reminder (art. 102 al. 2 CO). Even in this case, a written formal notice is still useful to set out the situation clearly and prepare the next steps.

Default has several consequences. The debtor is liable for the damage caused by the delay (art. 103 CO). If the obligation is a sum of money, the debtor owes default interest of 5% per year, even if a lower rate was agreed (art. 104 al. 1 CO). A higher contractual rate still applies (art. 104 al. 2 CO). If the damage exceeds this interest, the debtor must compensate it, unless they prove that they are not at fault (art. 106 CO).

In a bilateral contract, such as a sale or a contract for work and services, you can also set the defaulting debtor a reasonable deadline to perform (art. 107 al. 1 CO). If this deadline is not met, you can still demand performance plus damages for the delay. You can also waive the performance, provided you declare this immediately, and either claim compensation for the damage caused by non-performance or withdraw from the contract (art. 107 al. 2 and 109 CO). This deadline is not required in particular when it would obviously be pointless or when performance had to take place on a specific date (art. 108 CO).

A good letter of formal notice is short and precise. It states your contact details and those of the debtor, the date, the subject of the claim (invoice, contract, reference number), the exact amount in francs or the performance expected, and a clear final deadline, usually 10 to 30 days. Mention that if the debtor fails to perform you will take the necessary legal steps, and that default interest is accruing. Stick to the facts and avoid any disproportionate threats.

The law does not require any particular form, but it is up to you to prove the formal notice. So send the letter by registered mail and keep the receipt and a copy. Please note: a formal notice does not interrupt the limitation period. Only an acknowledgement of the debt by the debtor, debt enforcement or legal action has this effect (art. 135 CO). If the debtor admits owing the sum, have them sign an acknowledgement of debt: it interrupts the limitation period and serves as a title for provisional removal of the objection (mainlevée) in debt enforcement proceedings (art. 82 LP).

If the deadline passes without payment, the next step is to file a debt enforcement request with the office des poursuites (debt enforcement office) at the debtor's place of residence (art. 46 and 67 LP). You advance the costs (art. 68 LP), and you can include the default interest from the date of default.

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