Mandatory information on an invoice in 2026 (complete list)
Mandatory invoice information in 2026: identity, registration number, VAT mention, numbering, penalties — plus the new e-invoicing fields.
In short
- •An invoice must contain your identity + registration number + « EI », the client, a date, a unique sequential number, the details, the net / VAT / gross amounts and payment terms.
- •Under VAT exemption, add the VAT mention (« art. 293 B du CGI » until end 2026, then art. L. 233-3 du CIBS from 1 January 2027).
- •E-invoicing adds new mandatory fields (client SIREN, operation type, VAT payment option).
- •A missing mention = rejected invoice or a fine. Robi applies them all automatically.
Why mandatory information matters
An invoice is a legal document. A missing mention can get it rejected by the client, disputed, or expose you to a fine. The good news: the list is known, and a good tool handles it for you.
The complete list
The VAT mention (exemption regime)
Until 31 December 2026 the wording is « art. 293 B du CGI »; from 1 January 2027 it becomes « art. L. 233-3 du CIBS » (the change planned for September 2026 was postponed; the old wording stays accepted until 30 June 2028). See our VAT mention 2026 article.
What e-invoicing adds in 2026
With the e-invoicing reform, new mandatory fields appear on B2B invoices: the client's SIREN, the operation type, and the VAT-on-debits option where relevant — all inside the structured Factur-X format, not just the readable PDF.
Retention
You must keep every invoice for 10 years.
What about Robi AI?
Robi AI applies all mandatory mentions automatically and generates your invoices in the reform-compliant Factur-X format. You can even create one by voice.
The full workflow, from a spoken sentence to a Factur-X invoice, is explained on Robi's AI invoice page.
Conclusion
A compliant invoice is about forgetting nothing. Keep this list handy — or let a tool apply it for you.
Frequently asked questions
What information is mandatory on an invoice?+
Your identity with « EI » and SIREN, the client's details, the date, a unique sequential number, the itemised work, net/VAT/gross amounts, due date, late penalties and the VAT mention if exempt.
What's the risk of a missing mention?+
A non-compliant invoice can be refused or disputed, and the authorities can fine you per non-compliant invoice.
Does e-invoicing add mentions?+
Yes: the client's SIREN, the operation type and, where relevant, the VAT-on-debits option, inside the structured Factur-X format.
Put these tips into practice
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