Your French e-invoicing project won't fail on the XML. It'll fail on master data.
The September 2026 mandate is locked. Here is the gap most D365 teams don't see coming, and how to close it before go-live.
Most French e-invoicing programmes are aimed at the wrong risk. Teams pour months into UBL formats, PDP selection, and Peppol connectivity. Then they go live, and the invoices bounce. Not because the XML was malformed. Because the master data behind it was never clean.
Here's the truth: an electronic invoice is only as good as the customer and legal-entity data feeding it. Miss a SIRET, a VAT prefix, or an IBAN, and the file either fails validation up front or gets rejected after you've already sent it. Either way, a finance team that thought it was compliant is now firefighting invoices one at a time.
The deadline isn't moving
From 1 September 2026, every VAT-registered business in France must be able to receive electronic invoices, and large and mid-sized companies must also issue them. SMEs and micro-enterprises follow on 1 September 2027. The National Assembly rejected another proposed delay in April 2025, so the date is real and the runway is short.
The mechanics matter too. Invoices flow through accredited platforms (the Plateforme de Dématérialisation Partenaire, or PDP), while the Portail Public de Facturation acts as the central directory and data concentrator that routes each invoice to the right recipient and reports the data to the DGFiP. France now governs this on the Peppol network, and the format your invoices have to satisfy is Peppol BIS Billing 3.0, built on the EN 16931 European standard.
None of that connectivity helps you if the data inside the invoice is incomplete.
Where it actually breaks
The XML generator does exactly what you tell it. Whether you use the native Electronic Invoicing capability in Dynamics 365 Finance through a certified PDP, or a bespoke build, the generator reads your master data and emits it. It won't invent a SIRET you never captured. It won't guess an IBAN that isn't on the bank account. And a VAT number with the wrong country prefix goes out exactly as wrong as you stored it.
EN 16931 turns those gaps into hard failures. The seller name, postal address, and country code are mandatory. So are the buyer's. The SIRET drives the electronic address that identifies both parties on the network. The IBAN populates the payment account. A VAT identifier has to carry a valid ISO country prefix, and that prefix has to match the country it belongs to. Break any of these and Peppol validation stops the invoice.
Here's the part nobody budgets for: it's almost never one record. Master data gaps repeat. The same missing SIRET. The same blank IBAN. The same customers with no VAT number, copied across hundreds or thousands of accounts. Missing SIRETs and IBANs are the most common gaps I see on French legal entities, and they sit quietly until the first batch of invoices goes out.
You don't want to discover that on 1 September 2026.
Validate the data before you generate a single invoice
This is why we built the E-Invoice Readiness Check. It runs inside Dynamics 365 Finance, before any XML is generated, and scans your legal entity and every customer against the same rules a Peppol endpoint will apply.
On the seller side it checks the company name, full postal address, a valid two-character ISO country code, a VAT number with the right prefix for the country, a 14-digit SIRET, and a bank account that actually has an IBAN (plus a SWIFT/BIC where the receiver expects one). On the buyer side it checks name, address, country code, SIRET, VAT identifier and prefix, reverse-charge readiness, and the contact email and phone the invoice carries. It checks the payment setup too: that terms exist, and that the description landing in the invoice note isn't blank.
The output isn't a cryptic error log. It's a plain Excel report, one line per problem: the customer account, the rule it breaks, whether it's an error or a warning, the exact field, the issue in plain English, and the fix. A controller can work it like a punch list. A project lead can track it down to zero before cutover.
What most teams do, and what the ready ones do
Most teams treat master data as something they'll clean up "during testing." They generate invoices, submit through the PDP, wait for rejections, then chase each failure back to a customer record while the close clock is running. It's slow, it's manual, and it always lands when finance has the least time to spare.
The ready ones invert it. They validate master data in bulk, weeks before go-live, fix every gap once, and walk into 1 September with a clean dataset. Same destination. A fraction of the pain. It's also a far better starting point for what comes next, because the automation and AI agents everyone wants pointed at invoice processing only work when the data underneath them is trustworthy.
Your ERP is only as good as the processes behind it. E-invoicing just makes that brutally visible, on a fixed date, in front of the tax authority.
Don't find out on go-live day
If you're running D365 Finance and the French mandate is on your roadmap, the smartest hour you can spend right now is finding out how clean your customer and legal-entity data actually is.
That's what a readiness review gives you. Book a 30-minute session and we'll show you where your master data will break, and what it takes to fix it before it costs you a single rejected invoice.
FAQ
- When does French e-invoicing become mandatory? From 1 September 2026, all VAT-registered French businesses must be able to receive e-invoices and large and mid-sized companies must issue them; SMEs and micro-enterprises follow on 1 September 2027.
- What format do French e-invoices use? Peppol BIS Billing 3.0, based on the EN 16931 European standard, exchanged through accredited platforms (PDPs).
- Why do e-invoices get rejected at go-live? Most rejections trace back to incomplete master data: a missing SIRET, a VAT number with the wrong country prefix, or a bank account with no IBAN.
- How do I check my D365 data is ready? Run a master data validation against the EN 16931 rules across your legal entity and every customer before generating invoices. That's what the Dr Dynamics E-Invoice Readiness Check does.