Every collection file we open answers the same question twice: can the debtor pay, and what exactly may we claim? The second answer is written long before the dispute — in your own terms and conditions. Four clauses do most of the work.
1. A payment term, with interest for exceeding it
Say when payment is due and what happens when it is not. Belgian law provides statutory late-payment interest for commercial transactions, but a clear contractual term removes the discussion about when the clock started.
2. A compensation clause
A fixed percentage of the principal — 10% is the customary figure — payable on late payment. This is the clause that decides whether the cost of recovering your money comes out of your debtor's pocket or your own. Without it, you can recover the invoice; with it, you can recover the invoice and what it cost you to get it.
3. A complaints period
A short, defined period within which the invoice must be contested in writing, ideally by registered mail. It turns the general Belgian presumption of acceptance into a fixed date you can point at, and it is what keeps late objections out of your file.
4. Retention of title
Goods remain yours until they are paid for in full. Its value shows in exactly the situation you most fear: if your customer goes bankrupt, goods covered by a valid retention clause can be reclaimed rather than shared out among all creditors.
Peppol does not change any of this
Since structured e-invoicing became mandatory in Belgium on 1 January 2026, we are regularly asked whether terms and conditions remain enforceable when the invoice travels through the Peppol network. They do — and they do not become more enforceable either. Peppol is a technical transmission channel, not a legal safety net. The clauses still have to be communicated before the agreement is concluded and their acceptance still has to be demonstrable, exactly as before. Terms that appear for the first time on the invoice arrive after the contract was formed, whether that invoice is paper, PDF or Peppol.
Two conditions decide whether any of it works
When you communicate them. Terms printed on the back of the invoice arrive after the agreement is concluded. They belong on the quotation and the order confirmation — before your customer commits — and you should be able to demonstrate that your customer received them. For recurring customers, a framework agreement or a single explicit acknowledgement settles the point once and for all.
Who you are selling to. Business-to-business and business-to-consumer are two different legal worlds in Belgium: consumer protection rules restrict what you may stipulate and make some clauses unenforceable. Terms drafted for one do not simply work for the other — and terms drafted for another country rarely work here unchanged.
Upload your terms with your invoice. It is the single document that most improves what you get back — and if you have none, tell us: it changes what we can claim from your debtor.