Why clean the file before the reform
Since 1 September 2026, the customer's SIREN is one of the mandatory details on an invoice between businesses. A missing or incorrect SIREN, or one belonging to a closed company, exposes the invoice to rejection and delays payment. The timeline and the four new mandatory details are explained in the article E-invoicing 2026: why your customers' SIREN becomes mandatory; this page covers the method for fixing the file.
The fields to check
| Field | What to check |
|---|---|
| SIREN | 9 digits, correct check digit, existing company |
| SIRET | 14 digits starting with the SIREN: do not confuse it with the SIREN in the column |
| VAT number | Format and registration; in France it contains the SIREN, but does not replace it |
| Company name | Matches the name in the register |
| Billing address | Complete and up to date, with postal code and city |
| Status | Active company, not closed or in insolvency proceedings |
Duplicates and closed companies
A file built up over the years often contains the same company twice, under slightly different names ("Boulangerie du Centre" and "Centre Boulangerie"): the SIREN lets you match them. It also contains companies that have ceased trading: invoicing a closed SIREN produces a rejection. Spot them, then ask the customer for their new contact or new entity before the next invoice.
The 7-step method
- Export the file. A CSV, a text file or an Excel workbook from your invoicing software or your CRM.
- Locate the identifier column. SIREN, SIRET or VAT number: keep leading zeros by treating the column as text.
- Check the format and the check digit. Set aside numbers of the wrong length or with an incorrect check digit.
- Convert SIRETs and VAT numbers to SIRENs. The first 9 digits of a SIRET are the SIREN; in a French VAT number, the SIREN follows the check characters.
- Find the missing SIRENs. Search for the company by its name and city, then confirm the result before copying it over.
- Set aside closed companies. Flag them for separate handling, without deleting them blindly.
- Deduplicate and reimport. Merge the rows that share the same SIREN, then reload the file into your software.
By hand, these checks take hours on a file of a few thousand rows. With the API, the GET /v2/validate route runs them row by row; the offer below saves you from writing that code.
Before and after example
An illustrative extract, with fictional data, of what the diagnostic reveals: the anomaly found and the suggestion for each row.
| Customer (fictional) | Identifier in the file | Anomaly found | Suggestion |
|---|---|---|---|
| Customer A | 5520325 | 7-digit identifier | Look up the SIREN from the name and city |
| Customer B | 123 456 789 | Incorrect check digit (invalid_identifier) | Correct the likely typing error |
| Customer C | 14-digit SIRET | SIRET in the SIREN column | Convert to a SIREN, the first 9 digits |
| Customer D | Valid SIREN | Closed company | Stop invoicing this entity |
| Customer E | Valid SIREN, present on two rows | Duplicate | Merge the two rows |
After correction, each row keeps all your columns and receives the corrected identifier, the name, the status, the address, the VAT number and its status.
The offer: free diagnostic, correction from €29 excl. VAT
- Free diagnostic with no account. You see the state of your file before paying.
- Up to 5,000 rows: €29 excl. VAT. Up to 50,000 rows: €79 excl. VAT. Beyond that, on quote. One-off payment per file, no subscription.
- File deleted after 7 days. CSV, TXT and Excel formats.
Why this offer is different: no competitor identified in 2026 offers a one-off customer file cleanup, ready to reimport. Details and file upload are on the Customer file page.
Frequently asked questions
Why is the customer's SIREN mandatory on the invoice?+
Since 1 September 2026, it is one of the mandatory details on an invoice between businesses, and it is used to address the e-invoice to the customer's receiving platform.
How do I check a SIREN in an Excel file?+
Check the 9-digit length and the check digit of each row, then the existence of the company. Beyond a few dozen rows, upload the file for a free diagnostic.
What should I do with customers whose company is closed?+
Do not delete them blindly: flag them, check whether they have a new entity, then update the file before your next invoice.
Is the diagnostic really free?+
Yes, and with no account: one file per day. You only pay if you download the corrected file.
How much does cleaning a customer file cost?+
€29 excl. VAT up to 5,000 rows, €79 excl. VAT up to 50,000 rows, on quote beyond that. Payment is one-off, with no subscription.