What an invoice must carry

A graphic designer invoices an agency 3 400 €. He leaves out the due date, the late-payment rate and the early-settlement discount line. Three omissions at 15 € each: 45 €, capped at 25 % of the invoice, so 850 € at worst. And the next invoice bears the same number as the previous one. Before you read on: which of these mistakes is the most serious?

Two texts, one invoice

The mandatory particulars come from two sources that overlap. Article L441-9 of the commercial code imposes them between professionals; article 242 nonies A of annex II to the general tax code adds those required by VAT, for every taxable person.

An invoice therefore carries the full identity of both parties, the date of issue, the description and quantity of the goods or services, the unit price excluding VAT, the rate and amount of VAT by rate, and the total to pay.

To that are added the payment particulars: the date on which settlement must take place, the rate of late-payment penalties, the flat recovery indemnity, and the terms of any discount for early settlement.

The discount line is the one most often forgotten, because it looks pointless when none is granted. It is still due: where there is no discount, the invoice carries "Discount for early settlement: none".

• Identity: name and address of both parties, the seller's VAT identification number, company registration number, legal form and capital for a company.
• Transaction: date of issue, date of the sale or of the end of the service, description and quantity, unit price excluding VAT, discounts granted.
• VAT: applicable rate, amount of VAT by rate, total excluding and including VAT, or the exemption wording that stands in its place.
• Payment: due date, rate of late-payment penalties, flat recovery indemnity of 40 €, terms of any early-settlement discount.

A unique number, a sequence with no gap

Each invoice bears a unique number based on a continuous chronological sequence, with no break. Two invoices cannot bear the same number, and no number may be missing from the series.

It is the rule whose breach shows fastest in an audit: a missing number suggests an invoice withdrawn, a duplicate number suggests an invoice rewritten. The sequence is the first proof that the accounts are complete.

The invoice is drawn up in two copies: the original goes to the customer, the second is kept by the business. Invoices issued and received are kept for ten years; the period is reduced to six years for tax documents.

Nothing forbids restarting at one each year, provided the prefix keeps the series continuous: 2025-001 then 2026-001 form two readable runs. What the rule refuses is a number that is missing, or one that appears twice in the same run.

Two penalties, and they add up

An omitted or inaccurate particular costs 15 €, applied to each error. The total of the fines on one invoice may not exceed 25 % of its amount. That is the penalty for form, and it is counted line by line.

Not issuing an invoice at all falls under another regime. The tax fine reaches 50 % of the transaction amount, reduced to 5 % if the supplier proves, within thirty days of a formal notice, that the transaction was properly booked.

A criminal penalty is added: up to 75 000 € for a sole proprietorship, up to 375 000 € for a company. The two regimes do not exclude each other; one punishes the loss of tax revenue, the other the breach of a commercial obligation.