A reliable audit trail (PAF, piste d'audit fiable) is a set of documented and permanent internal controls that links each invoice to the delivery of goods or the service it bills, so a company can prove the authenticity of origin, the integrity of content and the legibility of its invoices under French VAT law.
A reliable audit trail is a tax-law evidence mechanism, which distinguishes it from a system audit trail that logs who changed what in a software. The PAF comes from Directive 2010/45/EU, transposed at article 289 VII of the French General Tax Code (CGI), and is detailed in the BOFiP guidance BOI-TVA-DECLA-30-20-30-20.
A reliable audit trail must guarantee three things for each invoice, from issue until the end of the retention period:
- Authenticity of origin: the identity of the supplier or issuer is assured
- Integrity of content: the invoice data has not been altered
- Legibility: the invoice can be read by the tax auditor
The CGI accepts three methods to meet those guarantees: a reliable audit trail, a qualified electronic signature, or EDI exchange. Under the PAF route, each company sizes its controls to its organisation, activity and invoice volume. In practice, the documentary chain runs from the purchase order to the goods received note, then to the invoice and its payment, and an auditor must be able to walk it in both directions.
Phacet builds that chain as a by-product of its controls. 3-way matching links each invoice line to its order and receipt, every match and every exception is timestamped, and the agent that can prepare your audit file automatically assembles the evidence when the auditor asks for it. The chain is the same when invoices arrive as structured Factur-X files, because the trail concerns the transaction, not the file format.
