Factur-X explained: the hybrid invoice format behind the 2026 reform

Factur-X in one sentence

A Factur-X invoice is a single PDF file carrying two things at once: the invoice you read on screen, and exactly the same information written as XML inside the file, for software to read.

That's it. No second file, no separate attachment, no portal to learn. You send a PDF — except this PDF knows how to be read by a machine.

Why the format exists

Until now a PDF invoice was a picture of an invoice. A human reads it, understands it, and retypes it into an accounting tool. That's slow, and it's where errors creep in.

Pure XML formats (UBL, raw CII) fix that but create the opposite problem: a human can no longer read anything without a tool.

Factur-X is the compromise: readable by both. That's why it caught on — the format was built jointly by France (FNFE-MPE) and Germany, where it is called ZUGFeRD. The two are technically the same format.

What is actually inside the file

A Factur-X invoice is three stacked layers:

| Layer | What it is | What it's for |

|---|---|---|

| PDF/A-3 | A PDF variant designed for long-term archiving that allows attachments | Making sure the invoice is still readable in 10 years |

| `factur-x.xml` | The XML file attached inside the PDF | Carrying the structured invoice data |

| XMP metadata | An internal declaration: "this is Factur-X, profile X" | Letting the recipient's software detect the format |

The XML itself follows two distinct standards that are easy to confuse:

Syntax : UN/CEFACT CII (*Cross Industry Invoice*) — the grammar, how tags are written.

Semantics : EN 16931 — the European standard defining *which* information an invoice must carry and how the amounts must add up.

EN 16931 is what requires, for instance, that line totals sum to the net amount, or that a VAT-free invoice carries an exemption reason. Those calculation rules have codes (`BR-CO-10`, `BR-CO-13`…) that a validator checks one by one.

Factur-X profiles

Not every Factur-X carries the same amount of data. The format defines several profiles, from lightest to most complete:

| Profile | Contents | Status |

|---|---|---|

| MINIMUM | Accounting essentials only (seller, total, VAT) | Not enough for a tax-valid invoice |

| BASIC WL | Without line items | Edge cases |

| BASIC | With line items | EN 16931 compliant |

| EN 16931 ("COMFORT") | The full European standard set | The reference profile |

| EXTENDED | EN 16931 plus Franco-German extensions | Advanced business cases |

If you remember one thing: the profile that matters is EN 16931. It ticks the complete European standard, and it is the one Robi generates.

Factur-X, PDF and e-invoicing: the confusion to avoid

Many freelancers assume they already do e-invoicing because they email PDFs. They don't.

A plain PDF sent by email is not an electronic invoice under the reform. It's a paperless paper invoice.

A Factur-X invoice is a compliant structured format, but it still has to travel through an accredited platform to satisfy the French obligation.

In other words: the right format is necessary but not sufficient. The format is your side of the job; transport is the platform's. The good news is that the format side is the one you can settle today, alone, without waiting.

For the full timeline and the role of platforms, read the guide on e-invoicing in 2026.

How to generate a Factur-X invoice

You cannot hand-craft a Factur-X: you need software that builds the XML, attaches it to the PDF and writes the right metadata.

Robi AI does it natively. You create your invoice as usual — by voice or by typing — and download it as Factur-X, EN 16931 profile. Before exporting, Robi checks that every field the standard requires is present (company ID, addresses, VAT number where applicable) and tells you exactly what's missing if anything is.

Official source: the French tax administration's e-invoicing portal details accepted formats and the timeline.

Takeaway

Factur-X isn't one more constraint: it's the format that lets you send one single thing — a PDF — and satisfy both your human customer and their accounting software. It's the step you can take now, five months ahead of the deadline.

To check your file, see how to test that a Factur-X invoice is valid.