The short answer
There is no format difference. What Germany calls ZUGFeRD, France calls Factur-X — the same PDF/A-3 shell, the same embedded CII syntax, the same profiles.
Generate a valid ZUGFeRD file and you have generated a valid Factur-X file without doing anything for it.
Where differences do lie
| ZUGFeRD | Factur-X | |
|---|---|---|
| Carrier | PDF/A-3 | PDF/A-3 |
| Embedded syntax | CII | CII |
| Profiles | identical | identical |
| Version counting | independent | independent |
| Prescribed delivery route | no | yes (approved platform) |
| Tax administration involved | no | yes (five-corner model) |
The bottom two rows are the only ones that create work in a project. And they do not concern the file.
The version trap
Both standards count separately. A statement like "we support 2.x" is therefore ambiguous without the standard's name — the numbers refer to different publications of the same aligned basis.
💡 In agreements always name both: standard and version, plus the profile. "ZUGFeRD 2.5, EN 16931 profile" is a complete answer. "We do ZUGFeRD" is not.
The difference that actually counts
Germany regulates e-invoicing between businesses through the document: it must be structured and conform to the standard. How it reaches the recipient is left to the parties — an email is enough.
France additionally regulates the route: invoices travel over approved platforms, and the tax administration receives data along the way. That is not a property of the format but of the process.
🔴 In projects the two get mixed regularly. Somebody reports "Factur-X does not work", and what is meant is that the platform attachment is missing. The file was never the problem.
Recommendation
Generate ZUGFeRD in the EN 16931 profile. That makes you conformant in Germany, format-conformant in France, and connectable in the rest of the EU, because the profile covers the core of the European standard in full.
Everything beyond that is a question of the delivery route — and that one is answered by the recipient, not by the specification.