The CII (Cross Industry Invoice) format is one of the e-invoicing formats officially accepted in France under the 2026–2027 reform, alongside Factur-X and UBL, but it remains the most prescriptive and structured for complex information systems.
With the gradual implementation of mandatory e-invoicing starting in 2026, French companies must adapt their practices and adopt e-invoice formats compliant with the new regulatory framework. This reform, which we detail in our complete guide to e-invoicing, mandates the use of structured formats recognized by the tax authorities, which now form the basis of B2B exchanges.
Among these formats, some are widely known, such as Factur-X or UBL. Others remain less common but play a strategic role in highly structured environments. This is the case for the CII (Cross Industry Invoice) format, an e-invoice format entirely structured in XML, designed for automated, standardized exchanges between information systems.
Unlike hybrid formats, CII does not aim to replicate a human-readable invoice. It prioritizes data accuracy, interoperability, and strict adherence to European standards, making it particularly suited for mature organizations, high-volume transactions, or international contexts.
However, the CII format is not a universal choice. Its suitability largely depends on your existing tools, Procure-to-Pay processes, and invoicing volumes. To better understand CII’s position relative to other authorized formats within the regulatory framework, you can also consult our page dedicated to e-invoice formats accepted in France.
In this guide, we will clarify what the CII format truly is, who it’s for, and in which contexts it represents the best choice.
What is the CII format?
The CII format, for Cross Industry Invoice, is a fully structured e-invoice standard, based exclusively on XML data. Unlike hybrid formats, CII does not include any visual document for human readability: it is designed from the outset to be automatically interpreted and processed by information systems.
The CII format was developed at a European level as part of the work by UN/CEFACT (United Nations Centre for Trade Facilitation and Electronic Business), an international body responsible for defining common standards for electronic business exchanges. Its objective is clear: to enable interoperable, reliable, and standardized invoice exchanges, regardless of the industry or country.
Within the context of e-invoicing, a CII format invoice is therefore a structured XML file, precisely and standardly describing all invoicing information. It notably includes:
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complete identification of the issuer and recipient (entities, identifiers, addresses),
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invoice references (number, issue date, currency),
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line-by-line details of products or services invoiced,
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tax-exclusive amounts, VAT, and totals,
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applied VAT rules,
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payment terms and conditions,
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order or contract references, if applicable.
All this information is encapsulated in standardized XML tags, which ensures uniform interpretation by software, without ambiguity or manual re-entry.
The CII format complies with European standard EN 16931, which defines the common core of mandatory data for e-invoices within the European Union. This compliance ensures that CII invoices comply with both French regulatory requirements and European standards, especially in cross-border exchange contexts.
In practice, CII primarily targets already highly digitized environments, where data exchanges are automated and direct human readability of the invoice is not a prerequisite. It is particularly suited for organizations with systems capable of generating, receiving, and utilizing complex XML flows, aiming to industrialize invoicing processes.
100% structured XML format, with no visual component
European standard from UN/CEFACT work
Compliant with EN 16931 standard
No native PDF, human readability only via tools
Designed for complex and interoperable information systems
Why CII is a Prescriptive XML Format (and what it implies)
The CII format stands out for its highly prescriptive nature. Where some formats primarily aim to facilitate adoption or transition, CII prioritizes strict compliance with international standards and precise data exchanges. This orientation has direct consequences on how it’s used and the contexts in which it is truly relevant.
Less pragmatic than a hybrid format like Factur-X, CII offers no compromise on human readability. It does not contain a PDF and does not aim to adapt to “paper” or semi-dematerialized uses. Conversely, it is more prescriptive than UBL in certain aspects, as it fits into a broader conceptual framework, designed for highly regulated intersectoral and international exchanges.
CII’s structure is rigid and highly standardized. Every piece of invoice information must be placed in a specific tag, following a strict data model. This rigor ensures uniform interpretation by information systems but leaves little room for approximations or local adaptations. Missing, poorly structured, or inconsistent data can lead to the outright rejection of the invoice.
This low tolerance for deviations is both a strength and a constraint. On the upside, the CII format offers a very high level of reliability, maximum data precision, and excellent interoperability between systems, including multi-country or multi-ERP contexts. It significantly reduces ambiguities and interpretation errors, which is crucial in complex environments.
In return, CII imposes a strong reliance on tools capable of correctly generating, controlling, and interpreting XML. It requires well-structured repositories, rigorous configurations, and high digital maturity. Without this technical ecosystem, the format quickly becomes difficult to use daily.
In summary, CII is not a “flexible” or “educational” format. It’s a demanding standard, designed for organizations that prioritize compliance, robustness, and large-scale interoperability, at the cost of higher operational complexity.
CII in French E-Invoicing: Role and Use Cases
Within the French e-invoicing framework, the CII (Cross Industry Invoice) format is one of the officially accepted formats.
Concretely, CII integrates into the new invoice circulation scheme, based on accredited platforms (PA) and the Public Invoicing Portal (PPF). The invoice is issued in CII via an accredited platform, transmitted to the recipient’s receiving platform, and then the necessary invoicing data is relayed to the tax authorities via the PPF, particularly for control and pre-filling VAT declarations.
CII’s role in this system is primarily that of a reliable and standardized data format, perfectly suited for automated transmission of tax information. Its rigorous XML structure facilitates the extraction, control, and utilization of VAT data by administrative systems, while ensuring high consistency across the various platforms involved.
In practice, the CII format is less common than Factur-X in the French market. It is rarely chosen as the default format, especially by SMBs and mid-market companies, as it does not offer human-readable support for the end-user and requires a more advanced technical environment.
CII is primarily used in highly structured environments, where exchanges are already standardized and largely automated: large organizations, international groups, industrial ecosystems, or multi-ERP contexts. In these specific cases, its rigor and alignment with international standards are a real advantage.
Thus, in French e-invoicing, CII is not a marginal format, but a specialized one, intended for specific use cases where precision and interoperability take precedence over ease of adoption.
CII vs UBL vs Factur-X: When CII is the Right Choice
Within the French e-invoicing framework, CII, UBL, and Factur-X are all legally compliant. The choice between these formats is therefore not based on regulation, but on the suitability of the format for your organization. CII stands out for its highly prescriptive and international positioning, making it relevant in specific contexts.
Format Comparison by Key Criteria
Human Readability
Factur-X is the only format to natively integrate a human-readable PDF. UBL and CII are pure XML formats, requiring a tool to generate a visual rendering. On this point, CII is the furthest from classic “documentary” uses.
Technical Complexity
CII is the most demanding format. Its highly standardized structure requires precise data configuration, strict compliance with XML schemas, and low tolerance for deviations. UBL is also structured but often perceived as more pragmatic. Factur-X remains the most technically accessible.
Volume and Automation
CII is particularly suited for high volumes and industrial flows. It allows for maximum automation of invoice processing, with a high level of reliability. The higher the volume, the greater the benefit of CII.
International Scope
CII is strongly oriented towards international interoperability. Originating from UN/CEFACT’s work, it is designed to operate in multi-country
