FEC and tax audits: the anomalies the tax administration spots in your accounts

When a tax audit begins, the first request is not a folder of invoices: it is a file. Article L47 A-I of the Livre des procédures fiscales (LPF), France's code of tax procedure, requires any taxpayer whose accounts are kept on a computerised system to hand over, "at the start of the audit operations", a copy of its accounting entries in electronic form. This file — the FEC, fichier des écritures comptables, the standardised accounting-entries file French companies must produce on a tax audit — is processed by software before an auditor has read a single line of it: the same article expressly authorises the administration to "carry out sorts, classifications and all calculations" in order to establish that the entries agree with the returns filed.

There is nothing opaque about this mechanism. The format is standardised and published, the list of fields is set out in the Livre des procédures fiscales, and the DGFiP (Direction générale des Finances publiques), France's tax administration, provides a free testing tool so that a company can check its own file. In other words: everything the administration will read in your FEC, you can read first. At doo.FINANCE we work with French SMEs that discover their FEC on the day of the audit. This article proposes the opposite — discovering it on a Sunday afternoon, with nothing at stake.

What the law requires, and when

Paragraph I of article L47 A of the LPF sets an obligation of form, not of substance: the taxpayer satisfies its obligation to produce accounting records "by handing over at the start of the audit operations, in electronic form meeting standards set by order of the minister responsible for the budget, a copy of the accounting-entry files".

Two procedures, two timetables:

• On-site audit of the accounts (vérification de comptabilité) — the FEC must be handed over "at the first on-site visit", according to the administrative doctrine published in the BOFiP (Bulletin officiel des finances publiques).
• Remote examination of the accounts (examen de comptabilité) — the company receives a notice of examination and has 15 days to send in its FEC. The administration then has six months to analyse the accounts, at the end of which it issues either a proposed adjustment or a notice that no adjustment will be made.

The obligation applies to taxpayers "keeping their accounts by means of computerised systems" and required by the CGI (Code général des impôts), France's general tax code, to keep and produce accounting records. The BOFiP exempts, among others, sociétés civiles immobilières whose partners are exclusively individuals, and auto-entrepreneurs.

Where the file is not produced, article 1729 D of the CGI provides for a fine equal to €5,000 or, where an adjustment is made and that amount is higher, a surcharge of 10% of the tax charged to the taxpayer. The doctrine specifies that it applies only once per audit, across all financial years.

One point that is rarely known, and reassuring: the same article L47 A-I provides that the administration destroys the copies of the files it has received before the tax is entered for collection.

First filter: the format, before the substance

A FEC is first accepted or rejected on its form. This stage is binary and says strictly nothing about the quality of your accounts — but a non-compliant file counts as a failure to produce, and the audit time limits are suspended until compliant files are handed over (article L52 of the LPF).

The 18 mandatory fields, in order

Article A47 A-1 of the LPF sets the list. For a company taxed under an actual-profit regime (BIC, industrial and commercial profits, or impôt sur les sociétés, corporate income tax), the file contains 18 fields, in this exact order:

#	Field	Content
1	JournalCode	The journal code of the accounting entry
2	JournalLib	The journal label of the accounting entry
3	EcritureNum	The number of the accounting entry, on a continuous sequence
4	EcritureDate	The date on which the accounting entry was posted
5	CompteNum	The account number, whose first characters must comply with the plan comptable français, the French chart of accounts
6	CompteLib	The account label, in accordance with the plan comptable français
7	CompAuxNum	The sub-account number (blank if not used)
8	CompAuxLib	The sub-account label (blank if not used)
9	PieceRef	The reference of the supporting document
10	PieceDate	The date of the supporting document
11	EcritureLib	The label of the accounting entry
12	Debit	The debit amount
13	Credit	The credit amount
14	EcritureLet	The matching code (lettrage) of the accounting entry (blank if not used)
15	DateLet	The matching date (blank if not used)
16	ValidDate	The date on which the accounting entry was validated
17	Montantdevise	The amount in foreign currency (blank if not used)
18	Idevise	The currency identifier (blank if not used)

The déclaration contrôlée regime and agricultural profits kept on a receipts-and-payments basis include additional fields. If you fall under one of them, have the applicable list checked rather than reusing this one.

The formal rules that make a file fail

The same article sets the technical standards. The points on which a file most often stumbles:

• Structure — a flat file with fixed zones, or a structured file coded in XML complying with the XSD specifications published by the administration.
• Encoding — ASCII, ISO 8859-15 or UTF-8, and nothing else.
• Dates — AAAAMMJJ format, that is YYYYMMDD, with no separator.
• Amounts — in decimal mode, right-aligned.
• First line — reserved for the field names.
• File name — in the form SirenFECAAAAMMJJ, the date being that of the financial year end.
• A single file — all the entries, all journals together, sorted in chronological order of validation.
• Scope — the entries after year-end inventory operations, excluding centralisation entries and account-balancing entries.
• Documentation — the file is accompanied by technical documentation describing the fields and the structure of the data.

None of these rules bears on the substance: a file that complies passes, a file that breaches them is sent back.

Second filter: what the structure of the FEC makes visible

A word of honesty: the DGFiP does not publish the list of substantive tests it applies. But you do not need it in order to prepare, because every mandatory field is, by construction, an available control point — and five of them are particularly telling as soon as the file is sorted.

The sequence of entries (EcritureNum)

The text is explicit: EcritureNum carries "the number of the accounting entry on a continuous sequence". Continuous. A gap in the numbering of a journal shows up on a simple sort and calls for an explanation: where did entry 4,517 go?

In practice, the leading cause of a break is not fraud, it is technical. A change of software mid-year, a carry-forward of opening balances, a journal recreated, a sequence reset on 1 January when the financial year does not match the calendar year: this is exactly where numbering breaks are born. We set out these traps in our article on changing accounting software mid-year. The anomaly is real, the intent is not — but it is for you to demonstrate that, and it is better prepared calmly, well ahead of time.

The two dates: posting and validation

EcritureDate carries the posting date, ValidDate the validation date. Because the file is sorted in chronological order of validation, the gap between these two dates is obvious from the first reading.

A lag of a few days is normal. A whole financial year validated over three days in November tells a different story: accounts caught up after the event, where the documents were entered long after the transactions they record. This is not unlawful in itself. But accounts validated as business happens are far easier to defend than accounts reconstructed afterwards.

Matching (EcritureLet, DateLet)

The text states that these two fields stay "blank if not used": the absence of matching is therefore not a non-compliance in itself. It does, however, have a heavy practical consequence. A customer account of four hundred lines, none of them matched, no longer allows a payment to be tied to an invoice. The balance becomes a lump, and justifying a lump takes days — yours, or your expert-comptable's.

The supporting document (PieceRef, PieceDate)

These two fields are mandatory. Three profiles naturally attract attention when the file is sorted: generic references repeated identically ("FACTURE", "DIVERS", "OD"), empty references on significant amounts, and PieceDate values falling outside the financial year concerned.

The accounts moved at the year end

Year-end inventory entries are legitimate and expected — the FEC explicitly includes them. What raises a question is not their existence but their profile: an abnormal volume of manual entries all dated the last day of the financial year, a suspense account (471) that swells at the close, adjustment accounts that absorb amounts with no document reference. Sorting by journal and by posting date is enough to bring that profile out — at the administration's end as much as at yours.

Test your FEC before you are asked for it

The DGFiP provides Test Compta Demat, a piece of software "available for free download" which "checks the validity of the structure of the company's file and indicates in particular the points where anomalies have been detected". The administration describes the operation as "simple, secure and confidential": the software runs on your own computer. A telephone helpline is open on 0809 400 210.

What the tool does: it checks the structure. What it does not do: it does not judge whether your accounts are truthful. A file that passes the test is not a file above suspicion — it is a file that will not be rejected on form. That is already most of the friction avoided.

Three further checks, to be carried out yourself in a spreadsheet from the exported FEC:

1. Continuity — sort by JournalCode then EcritureNum, and look for gaps in the numbering.
2. Validation lag — calculate ValidDate minus EcritureDate, then look at the distribution rather than the average: it is the extreme values that speak.
3. Missing documents — filter the lines where PieceRef is empty or generic, and sort them by descending amount.

Half a day, once a year, after the close. It is probably the best effort-to-peace-of-mind ratio of the whole financial year.

What accounts kept in an ERP produce by construction

Most of the anomalies described above are not corrected: they are prevented, at the level of the tool. Accounts kept in a properly configured ERP produce five properties without anyone having to think about them:

• Numbering — one sequence per journal, incremented by the system, never typed in by hand.
• Time-stamping — validating an entry sets a validation date that the user does not choose.
• Matching — built into the bank reconciliation flow, not added at the end of the year.
• The document — the invoice stays attached to the entry, not filed away in a parallel folder.
• The audit trail — every entry remains tied to the document and the transaction that produced it.

A spreadsheet produces none of these five properties. Well-configured accounting software produces all of them — provided the configuration was actually done and the sequences were not broken during a data migration. If your tool was put in place mid-year, or if you migrated from another package, that is the point to check first. Our Odoo accounting services include this check.

The same traceability logic governs the e-invoicing reform: invoices routed through an Approved Platform (Plateforme Agréée, PA — formerly PDP) arrive identified and time-stamped, which feeds directly into the quality of the FEC. We set it out in our article on Odoo as an Approved Platform for e-invoicing in France.

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