Invoices are a key part of any business activity. They record transactions between two parties and serve as accounting proof in disputes or audits. For invoices to be legally compliant, they must meet specific criteria, including numbering.

How should invoices be numbered? What are the requirements? This article covers the most frequently asked questions about invoice numbers in France.

What’s in this article?

• What is an invoice number?
  
• Why you should number invoices
  
• What regulations apply
  
• How to number your invoices
  
• How to number pro forma invoices, deposit invoices, and credit notes
  
• How to change the number of a previously issued invoice
  
• Penalties for non-compliance with invoicing regulations
  

What is an invoice number?

The invoice number is a unique identifier assigned to every invoice a business issues, regardless of its legal form. The number is a required invoice component in France. To comply with legal requirements, invoice numbers must follow a continuous, chronological sequence.

Why you should number invoices

Businesses can benefit from assigning a number to each invoice. Individual, chronological numbering:

• Helps manage and track invoices more easily, as it allows the business to organise and identify invoices

• Enhances invoice accounting

• Reduces the risk of confusion or billing errors

• Helps businesses avoid financial penalties that can result from non-compliance with legal requirements

Invoice numbers are also helpful to tax authorities, as they allow tax authorities to verify invoice compliance and combat fraud more effectively.

What regulations apply

Invoice numbering is regulated under the French Commercial Code and General Tax Code (CGI). Under Article 242 nonies A of the CGI, every invoice must be assigned a unique number. The numbers must follow an unbroken, continuous, and chronological sequence – you cannot repeat or omit numbers in the sequence.

In the case of multiple-page invoices, the unique invoice number must appear on every page of the invoice. The invoice number must be clearly displayed, but there are no rules about specific placement on the document.

Finally, the invoice number must be included on the invoice when it’s issued. Invoices cannot be numbered after they’ve been issued.

How to number your invoices

Business owners can choose the invoice numbering system that works best for their business. They can add a prefix referencing a time frame or include letters. For example, businesses could use formats, including:

• Year-number

• Year-month-number

• Letter-number

The invoice number can start with any digit; it doesn’t have to start with a zero. Here are some examples of numbered invoice sequences:

• Sequential numerical series: Invoices 03, 04, 05, etc.

• Sequential numerical series with a prefix referencing the year: Invoices 2025-03, 2025-04, 2025-05, etc.

• Sequential numerical series with a prefix referencing the year and month: Invoices 2025-03-03, 2025-03-04, 2025-03-05, etc.

Different numbering series

If a business has multiple invoicing locations (e.g. online and physical stores or several physical locations), it can set up a different numbering sequence for each location. Different sequences can also be used to distinguish between customer types (e.g. individuals vs. businesses) or billing formats (e.g. paper vs. electronic invoices).

For example, a business with one branch in Paris and another in Lyon might use the letters “PAR” at the start of the series for invoices issued in Paris and “LYN” for those issued in Lyon:

• Paris: Invoices PAR-03, PAR-04, PAR-05, etc.

• Lyon: Invoices LYN-05, LYN-06, LYN-07, etc.

You can change the numbering system during the year, but it’s best to wait until the fiscal year ends to avoid issues with the tax authorities.

How to number pro forma invoices, deposit invoices, and credit notes

Pro forma invoices are provisional invoices, so they’re not required to have numbers. However, you can number them if you choose. It’s important to use a sequence different from the one used for regular invoices.

On the other hand, deposit invoices are considered actual invoices for legal, commercial, and accounting purposes. Their numbers should be included in the regular numbering sequence used for standard invoices.

Credit notes can be included in the regular invoice numbering sequence or be assigned their own separate numbering sequence.

How to change the number of a previously issued invoice

To ensure a proper record of all transactions, tax authorities don’t allow invoices to be deleted or edited after issuance. To correct the number of a previously issued invoice, you must create a credit note. This allows you to cancel the invoice with the wrong number and issue a new one. The new invoice should be assigned the number that follows in the continuous, chronological sequence.

Penalties for non-compliance with invoicing regulations

Businesses that don’t comply with invoicing regulations can face fines of €15 for each error or missing piece of information. However, total fines are capped at 25% of the total invoice amount. Learn more about the penalties for non-compliant invoices.

Advanced invoicing tools such as Stripe Invoicing can help you avoid billing errors and related fines by automating the creation of compliant invoices, speeding up payments, and improving revenue tracking – no coding required.