What is the reliable audit trail (piste d'audit fiable)?

In practice, in France

The French tax code (code général des impôts) recognises three ways of securing those three guarantees: a qualified electronic signature, compliant EDI exchange, or — for every other invoice, including a PDF sent by email — the reliable audit trail. It is therefore the default regime for most SMEs today.

In practice, the business needs to be able to show the path: purchase order, delivery note, invoice, payment, and the controls linking them together. That path must be documented, not just practised — the tax authorities ask for a written description of the process, and its absence is itself a failing.

The stakes are not theoretical: it is the right to deduct VAT that is at issue. A defective audit trail can be used to challenge it.

In Odoo

Odoo natively holds a good part of the trail: matching between order, receipt, and invoice, the traceability of changes, and the link between the document and the entry.

What it does not do is write the description of the process. That still has to be produced, and it is the first thing asked for.

Common mistakes

• Assuming electronic invoicing will make the audit trail unnecessary: it is still required for everything outside that system.
• Carrying out the controls without describing them anywhere.
• Validating supplier invoices without matching them to the order and the receipt — the path is then broken at its central link.