Archiving Your Faxes in 2026: Retention Periods, Evidence and Filing

Short answer: a fax only becomes evidence the moment you can produce three elements together — the document exactly as it went out, the transmission report showing the number dialled, the date, the time and the number of pages, and a record of who sent it. Separately, they are worth almost nothing. Retention periods, meanwhile, do not depend on the fax but on the content: ten years for an accounting record, five years for a commercial contract, twenty years for a hospital medical file. The storage format matters as much as the duration: a PDF that will still be readable in fifteen years, not a pile of faded thermal paper or a proprietary file locked inside a platform.

The question always comes up after the incident, never before. A client disputes having received a formal notice sent eighteen months ago. An accountant asks for proof of an instruction transmitted to a bank. A court registry requests evidence of a filing made before the deadline. At that point, "we definitely faxed it" carries no weight. What carries weight is a dated, complete file produced in thirty seconds.

Here is how to organise the archiving of faxes — both incoming and outgoing — so that it holds up on the day someone asks.

What you need to keep: the evidence triptych

A fax is not an authenticated instrument. Under French law it falls within the regime of free proof between traders (Article L.110-3 of the Commercial Code) and, otherwise, within the court's sovereign assessment. In practice, the judge looks at the consistency of a body of indications. Three items make up that body.

The document itself, in exactly the state in which it was sent: cover sheet included, with the same pagination and the same layout. If you faxed a six-page contract, archive six pages — not the Word source file that has been edited since.

The transmission report (or send confirmation). This is the item most often lost, and the most important one. It must show the number dialled, the timestamp, the call duration, the number of pages transmitted and the status. Online fax services send it back by email: that email is an archive record, not a read receipt to be deleted.

The internal sending record: who pressed "send", and from which account. On a shared fax machine, that information simply does not exist — which partly explains why organisations are migrating to named fax-to-email solutions. On a platform, it appears in the activity log.

A fourth element helps a great deal and costs very little: proof that the number was the right one. A screenshot from an official directory, the letterhead of a letter from the recipient, a page from the RPPS register for a healthcare professional. This defuses the classic line of defence: "that isn't our number".

For how long? Retention depends on the content

There is no such thing as a "fax retention period". There are retention periods for documents, whatever channel they travelled through. The benchmarks below are based on the Commercial Code, the Book of Tax Procedures, the Labour Code and the Public Health Code — the references published by Service-Public.fr and by the chambers of commerce draw on the same sources.

Two important nuances.

First, the useful retention period is sometimes longer than the mandatory one: nothing stops you from keeping a transmission report for ten years if the contract it accompanies is subject to a ten-year limitation period. Second, the GDPR imposes the opposite constraint for personal data: you cannot keep everything indefinitely "just in case". Article 5(1)(e) enshrines storage limitation, and the CNIL checks precisely this point during inspections. A job application received by fax and not shortlisted may be kept for a maximum of two years, not ten.

Hence the simple rule: one retention period per document category, written down in a table, with a scheduled purge. Not one period per channel.

Format: aiming for fifteen years of readability

This is where the traditional fax loses from the outset. The thermal paper used by older fax machines fades within two to five years depending on exposure to light and heat; a 2022 fax kept in a folder near a window may already be partly illegible. If you still hold archives of this kind, the only useful action is to digitise them now, before the contrast disappears altogether. A duplex document scanner with automatic feeder can process a few thousand pages in a day and makes the job bearable.

For digital archiving, three choices matter:

The format. PDF/A (ISO 19005) is designed for exactly this purpose: everything is embedded in the file, fonts included, and nothing depends on an external resource. Multipage TIFF images, the native format of many fax gateways, remain readable but are bulky and poorly indexed. Convert to PDF/A and, if possible, add a text layer using optical character recognition: a fax processed by OCR becomes a document you can find by full-text search, which changes everything after three years of archives.

The resolution. Keep the resolution as received; do not recompress. A fax in fine mode is already at the edge of legibility; running it through aggressive compression to save 40 KB amounts to manufacturing a challengeable document. We cover scanning settings in detail in our article on illegible faxes.

Integrity. Two mechanisms complement each other. The first is the digital fingerprint (hash) calculated at the time of archiving: it proves the file has not been altered. The second is a qualified timestamp, within the meaning of the European eIDAS Regulation, which provides an enforceable date. Both are only essential for high-stakes files — foreseeable litigation, public procurement, sensitive accounting records. For everyday traffic, write-once storage is enough.

Naming and filing: the part that decides everything

An archive you cannot find does not exist. Naming is therefore the real infrastructure.

Here is a convention that works, tried and tested in professional practices as well as in administrative departments:

YYYYMMDD_HHMM_DIRECTION_RECIPIENT_SUBJECT_Npages.pdf
20260929_1042_OUT_nanterre-registry_filing-submissions-dupont_6p.pdf
20260929_1512_IN_biosud-lab_test-results-M4412_3p.pdf

Four principles lie behind this apparent heaviness:

• The date first, in YYYYMMDD format: alphabetical sorting becomes chronological sorting, in any system.
• An explicit direction (IN / OUT): nobody has to wonder six months later whether the document was received or sent.
• No accents, no spaces, no slashes: file names survive migrations, exports and ZIP archives.
• The number of pages: this is the first completeness check. A file announced as 6 pages that contains only 4 immediately flags a problem.

The transmission report is filed next to the document, with the same prefix and the suffix _report. Two neighbouring files are better than a report lost in an email inbox. Organisations with the highest volumes merge the two into a single PDF: the document, then the report as the last page. This is the most robust solution, because it makes separation impossible.

As for the folder tree, a three-level structure is almost always enough: Year / Business category / File. Beyond that, you are building labyrinths. And for residual physical archives, cardboard archive boxes with spine labels remain the most readable solution ten years later — provided you write the destruction date on the label, not just the opening date.

Where to store: three copies, two media, one off-site

The so-called 3-2-1 rule, popularised by backup professionals and echoed in ANSSI's resilience recommendations, applies as-is to fax archives: three copies of the data, on two different types of media, with one off-site.

In practice, for a small business or a professional practice:

1. The working copy, on the office server or NAS, indexed and accessible.
2. A copy on removable media — an encrypted external hard drive kept in a safe and rotated monthly.
3. A copy held by a third party: European online storage, or retention by your online fax provider if its contract explicitly provides for it.

Three recurring pitfalls.

The single-platform trap. Many fax-to-email services keep received faxes for 6, 12 or 24 months, then delete them. If your only archive is the provider's history, your real retention period is the one set by its contract — not the one set by the Commercial Code. Check the clause, and export periodically. On the receiving side, our guide to receiving a fax by email sets out the points to watch.

The personal inbox trap. A fax delivered to the address of an employee who leaves the company disappears along with their mailbox. Incoming faxes must arrive in a shared mailbox, with a rule for automatic archiving to the document repository.

The unpowered media trap. A USB stick forgotten in a drawer is not a backup: flash memory degrades without power, and error rates rise after a few years. For long-term archives, an encrypted external hard drive that is woken up and checked twice a year is better than a stick untouched since 2021. And if you encrypt, make a note of where the key is: a hardware password manager or a simple code notebook in a safe avoids the perfectly preserved yet permanently inaccessible archive.

What auditors really look at

When a tax inspection, a quality audit or opposing counsel examines your fax archives, the questions are always the same:

• Is there a written policy? One page is enough: categories, retention periods, formats, owner, purge date.
• Are the retention periods actually applied? A 2009 file still sitting there when the policy states five years is a negative signal from a GDPR standpoint.
• Are the documents complete? Document + report + verified number.
• Is the chain traceable? Who sent it, who has access to the archive, who deleted what and when.
• Has a retrieval test been carried out? Ask someone to find a specific fax from two years ago, stopwatch in hand. Beyond five minutes, your archiving is theoretical.

This last test is the most revealing and the least practised. Do it once every six months, at the same time as your business continuity test.

Purging: the forgotten half of archiving

Archiving without purging produces a heap, not an archive. And a heap is a risk: the more personal data you keep beyond what is useful, the more serious any breach becomes, and the more you expose yourself to a breach of the storage limitation principle.

Set up an annual purge, on a fixed date, on a simple principle: anything past the retention period set for its category goes, unless it is sealed for ongoing litigation. That exception must be explicit and documented — it is known as a litigation hold, and it suspends the purge over a named scope.

For paper, destruction must be irreversible. A cross-cut document shredder at level P-4 within the meaning of DIN 66399 is the minimum for documents containing personal data; lower levels produce strips that can be reassembled. For digital media, logical erasure is not enough on a decommissioned drive: encrypt from the outset and then destroy the key, or physically destroy the media.

Frequently asked questions

Does a fax that has been scanned and then destroyed retain its value?

Yes, provided the digital copy is faithful and durable. The French standard NF Z42-026 governs faithful digitisation, and Article 1379 of the Civil Code grants a reliable copy the same evidential weight as the original. In practice: scanning at sufficient resolution, a durable format, a calculated hash, and a written procedure describing the operation. Without that procedure, destroying the original weakens your position.

Does the transmission report prove receipt?

It proves that a call reached a fax machine and that N pages were transmitted to a given number. It does not prove that a human read the document, or that the right department received it. That is why the fax remains a form of evidence assessed at the court's discretion, and why it is better to pair it with a second channel for critical sends. We develop this point in our article on the legal value of the fax.

Should we keep faxes we receive that are not intended for us?

No — and you really should not. A fax that arrives by mistake contains data you are not the intended recipient of. Best practice: notify the sender, destroy it, and log the incident in one line in a register. Keeping it "as proof" creates the very problem you were trying to avoid.

How long does an online fax service keep my documents?

That depends entirely on the contract: from a few weeks to several years. Always treat the provider's history as a convenience, not as a legal archive, and plan for regular exports to your own storage. The list of destinations and the terms of use are set out on the supported countries page.

Can a fax replace registered post?

No, except where a statute or a contract expressly provides for it. Qualified electronic registered delivery, governed by eIDAS, carries a presumption that the fax does not. For a formal notice or a notification triggering a deadline, the fax is a way of gaining speed, not a substitute.

Key takeaways

• Three items make the evidence: the document, the transmission report, the record of the sender — archived together, ideally in a single PDF.
• The retention period depends on the content, not the channel: 10 years for accounting, 5 years for commercial matters, 20 years for hospital medical files.
• The GDPR sets the upper limit: keeping data beyond what is useful is a breach, not a precaution.
• PDF/A + OCR for readability fifteen years on; never aggressively recompress a fax that is already at the limit.
• YYYYMMDD dated naming, IN/OUT direction, page count: chronological sorting and completeness checking come for free.
• 3-2-1: three copies, two media, one off-site — and never rely on the provider's history alone.
• Purge on a fixed date, with a documented litigation hold for ongoing disputes, and irreversible destruction of paper containing personal data.
• Test retrieval twice a year, stopwatch in hand: if finding a fax from 2024 takes more than five minutes, your archiving exists only on paper.

You can send your next fax from the sending form and file the report you receive straight away: it is the step that costs thirty seconds today and saves a case file two years from now.