Short answer: a fax isn't kept "separately". It follows the same legal retention periods as the document it carries — 10 years for an accounting record, 5 years for a commercial contract, 20 years for a medical file from the last consultation. What changes with fax-to-email is the form: you archive a PDF and its transmission report, ideally timestamped and stored in duplicate. Without that discipline, a fax loses most of its evidentiary weight before a judge.
Through our contact form we regularly receive a question that comes in twenty different wordings: "I sent my fax, I got the confirmation — how long do I keep this?" Behind that ordinary query lies a genuine document-management issue, and a stubborn confusion between three distinct things: the document that was faxed, the proof of sending, and the medium on which both sit for years on end.
Let's sort it out, with concrete retention periods and a method you can apply this week, whether you're a tradesperson, a three-person practice, or an individual who sends three faxes a year.
What you're really archiving when you archive a fax
Three objects, three regimes
Sending a fax actually produces a small cluster of files, and many users keep only one of them — often the wrong one.
- The source document. The contract, the invoice, the prescription, the cancellation letter. This is what carries the content and triggers the legal retention period.
- The transmission report. The report generated by the fax service: number dialled, date and time, page count, status (
OK,failed,busy), and often a thumbnail of the first page. This is your proof of sending. - The activity log. The entry in your fax-to-email account history, or the confirmation email received in your inbox. It amounts to third-party confirmation.
Under French law, article 1366 of the Civil Code provides that an electronic document has the same evidentiary force as a paper one, provided its author can be identified and it is created and stored under conditions guaranteeing its integrity. In practical terms: it is the quality of your record-keeping that creates the value of your evidence, not the mere fact of having sent a fax. A PDF renamed twelve times and floating around a Windows desktop guarantees nothing at all.
A fax has no retention period of its own
There is no legal text setting "the retention period for a fax". A fax is a channel, not a legal category. The period to apply is that of the document being transmitted, as summarised by the service-public.fr portal (section "Durée de conservation des documents pour les entreprises") and as the CNIL reiterates in its guidance sheets on retention periods.
| Type of faxed document | Indicative retention period | Usual legal basis |
|---|---|---|
| Customer or supplier invoice, purchase order | 10 years from the close of the financial year | Commercial Code, art. L123-22 |
| Accounting records and books | 10 years | Commercial Code |
| Commercial contract concluded electronically | 5 years (10 years if the amount is ≥ €120,000) | Consumer Code / Civil Code |
| Payslip (employer's copy) | 5 years | Labour Code, art. L3243-4 |
| Tax returns and supporting documents | 6 years | Book of Tax Procedures, art. L102 B |
| Hospital medical file | 20 years from the last stay | Public Health Code, art. R1112-7 |
| Routine commercial correspondence | 5 years | General limitation period, art. 2224 Civil Code |
These periods are safety minimums, not maximums. The GDPR imposes the opposite requirement: once the purpose has been exhausted and the legal period has elapsed, personal data must be deleted or anonymised. Keeping "everything, forever" isn't cautious — it's non-compliance.
Current, intermediate and permanent archiving: the vocabulary that clears everything up
Archivists distinguish three ages of a document, and that framework works perfectly for faxes.
- Current archiving: the document is active, consulted every week. It lives in your inbox or your working folder.
- Intermediate archiving: it is no longer useful day to day but is still covered by a legal period or a litigation risk. It should be taken out of the inbox and filed in a dedicated, read-only space.
- Permanent archiving: heritage preservation, rare for a small business, common in regulated professions.
The most widespread mistake is letting the document's entire life play out inside the mail client. An inbox is not an archiving system: it is editable, can be purged by accident, depends on an account that may be closed, and is often shared. Moving from current to intermediate — that is, extracting and filing — is the step that genuinely protects you.
The 3-2-1 rule, still valid
The backup rule most often cited by ANSSI in its cyber-hygiene guides comes down to three numbers: 3 copies of the data, on 2 different types of medium, with 1 off-site. For a practice or a small organisation, that means in concrete terms: the workstation, an encrypted external hard drive stored somewhere other than next to the computer, and a European cloud space. A desktop NAS enclosure plays the role of the second medium very well as volumes grow, with the added benefit of handling disk redundancy itself.
For organisations handling paper documents before sending, a duplex document scanner with an automatic feeder is a game changer: it produces clean multi-page PDFs directly, with text recognition, avoiding the paper-fax-then-scan-afterwards routine.
Which file format will last twenty years?
PDF, yes — but preferably PDF/A
A fax received by email almost always arrives as a PDF or a TIFF. Ordinary PDF is convenient but allows elements whose long-term readability isn't guaranteed: non-embedded fonts, dynamic content, external links.
The PDF/A format (ISO 19005 standards) was designed precisely for archiving: everything is embedded in the file, nothing depends on the environment. It is the format recommended by the Service interministériel des Archives de France and by most public document-management frameworks. Most office tools can export to PDF/A; it's a checkbox, not a project.
Multipage TIFF, historically the fax's native format, remains perfectly readable and lossless, but it is heavy and poorly indexed by desktop search engines. Convert it to PDF/A when it enters the archive folder, keeping the original if the document is sensitive.
To be avoided for archiving: JPEG (lossy compression, no multipage support), screenshots, and above all the smartphone photo of a fax — handy as a stopgap, disastrous as evidence.
Naming is already archiving
A well-constructed file name is worth more than a badly used document-management system. One convention that has proved itself:
2026-08-29_FAX-ENVOI_DUPONT-SARL_facture-2026-0412_OK.pdf
ISO date (automatic chronological sorting), type, counterparty, subject, status. No accents, no spaces, no special characters: your files will survive system changes. And for the physical organisation of the workstation, a simple lever arch archive file remains unbeatable for the paper originals that law or practice requires you to keep in hard copy.
Evidentiary-grade archiving: when do you need to go further?
What the term covers
We speak of evidentiary-grade electronic archiving when the system guarantees three verifiable properties: integrity (the document has not been altered), traceability (you know who did what and when) and durability (the document remains readable over time). In France, the reference standard is NF Z42-013, adopted internationally as ISO 14641. It describes the requirements for an electronic archiving system (EAS): a digital fingerprint for each file, a tamper-proof event log, and documented retrieval procedures.
The European eIDAS regulation completes the picture with qualified trust services, notably qualified electronic timestamping, which creates a presumption as to the accuracy of the date and the integrity of the timestamped data. The list of qualified providers is published by ANSSI and can be consulted on the European Trusted List.
Who actually needs it?
Let's be honest: a certified EAS is overkill for a tradesperson who sends twelve faxes a year. The question to ask is one of risk: what happens if the other party disputes having received this document?
- Low risk (appointment confirmation, sending documentation) → careful backups, clean naming, the 3-2-1 rule. That's enough.
- Medium risk (cancellation, formal notice, binding order) → keep the trio of document + transmission report + confirmation email, in a read-only folder, and back it up with a registered electronic letter if the financial stakes are real.
- High risk (foreseeable litigation, health documents, insurance files) → qualified timestamping, or even a digital safe compliant with NF Z42-020.
A word on the physical security of the medium: if you store sensitive archives on an encrypted external hard drive, bear in mind that hardware encryption is no substitute for a password policy. And for paper documents due for destruction at the end of the legal period, a cross-cut document shredder is the bare minimum — the CNIL regularly penalises documents abandoned in open skips.
The special case of the transmission report
This is the most neglected item, and yet the most useful. French case law has repeatedly held that a fax transmission report constitutes prima facie evidence, but that on its own it does not prove the content of what was transmitted. It attests that a communication took place between two numbers, at a given time, over a given number of pages.
Hence the method: archive the report and the document together, in the same folder, under the same naming identifier. Apart, they are worth almost nothing; together, they form a coherent body of evidence (number dialled matching the recipient, page count matching the document, timestamp consistent with the context).
Practical tip: if the fax carries real stakes, follow up the transmission with an email to the recipient stating the time of sending and the number of pages. Silence from the other side for months considerably weakens any later challenge.
And keep a record of receipt too, not just of sending. An incoming fax archived with its header (the TSI, the field identifying the sender) and the notification email is a far stronger item than a bare PDF stripped of its context.
An archiving routine in five steps
- Create a stable folder tree:
Archives / Year / Faxes-sentandFaxes-received. Two levels are enough; full-text search does the rest. - Extract from the mail client once a month. Block out twenty minutes, drag the month's PDFs into the folder tree, rename them according to the convention.
- Convert to PDF/A the documents that matter, keeping the original if needed.
- Back up using the 3-2-1 rule, with at least one copy off the premises.
- Purge at the end of the period, keeping a small register of deletions — this is what the GDPR calls demonstrating compliance.
For regulated professions that need to formalise this routine, a handbook on document management and electronic archiving is a reasonable investment: it provides the procedure templates auditors ask for, and saves you from reinventing an already standardised framework.
Frequently asked questions
Does a fax that has been scanned and kept as a PDF have the same value as a paper original?
Since Decree no. 2016-1673 on the reliability of copies, a reliable digital copy has the same evidentiary force as the original, provided the reproduction process guarantees integrity and durability. A PDF/A scan, timestamped and kept in a traceable system, falls within that framework. A sloppy scan with no traceability will remain open to challenge.
How long does my online fax service keep my documents?
This varies widely from one provider to another, from a few weeks to several years. Never rely on your provider's history as your only archive: it's a convenience, not a guarantee. Read the retention clause in the terms and conditions, and export regularly.
Do I have to keep the paper fax after scanning it?
For most administrative documents, no, provided the digital copy is reliable within the meaning of the 2016 decree. Exceptions remain: notarial deeds, documents bearing a handwritten signature whose original is required, items an authority requires in original form. If in doubt on a high-stakes matter, keep the original until the limitation period expires.
Does the GDPR require me to delete my faxes?
It requires you not to keep personal data beyond the period necessary for the purpose pursued, extended by any applicable legal periods. A fax containing health data, bank details or HR information must therefore be subject to a planned purge, not simply forgotten.
Can a received fax count as a valid formal notice?
It may qualify as a formal notice within the meaning of article 1344 of the Civil Code, which imposes no particular form, but the burden of proving receipt will fall on the sender. Where the stakes are significant, a registered letter — postal or electronic within the meaning of eIDAS — remains the safer option.
In summary
- A fax has no retention period of its own: apply that of the document it carries (10 years for accounting, 6 years for tax, 5 years for most contracts, 20 years for a hospital medical file).
- Archive the trio: document + transmission report + confirmation email, in the same folder and under the same identifier.
- Get your faxes out of the inbox: a mail client is not an archiving system.
- Favour PDF/A and ISO-date naming, without accents or spaces.
- Apply ANSSI's 3-2-1 rule: three copies, two media, one off-site.
- Step it up (qualified timestamping, NF Z42-013, digital safe) only where the risk of a dispute is real.
- Purge at the end of the period: the GDPR also penalises excessive retention, not just data breaches.
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