Case study: the real cost of going without an accountant

Quick answer. Going without a chartered accountant exposes you to heavy tax penalties: 10 to 40 % surcharges (French Tax Code art. 1728 and 1729), 0.20 % late interest per month (art. 1727) and 5 % on VAT paid late (art. 1731). On a single year that goes off track, the bill often exceeds annual fees.

The question is almost never asked calmly. It surfaces when a director receives a proposed adjustment, discovers VAT wrongly collected over three quarters, or realises at sale time that the accounts do not hold up. To decide properly, it is better to reason on concrete figures than on intuition.

We offer here a reconstructed, anonymised case that aggregates situations frequently met in clean-up files. No fee figure is presented as an official rate: the profession has no fee scale, fees are free and set by the engagement letter.

Take a trading company, subject to corporate income tax, with turnover of around 480,000 euros. The director, comfortable with a spreadsheet, kept the books for two financial years to save on fees. He filed VAT, submitted his tax returns on time and paid his corporate tax. On paper, everything looked under control.

Reality appeared when changing banks, which asked for an attestation of accounts, then with a fundraising plan. That is when we were engaged for a clean-up mission. The review revealed several structural errors, none of them deliberate.

This situation is not exceptional. In clean-up files after self-management, the most frequent sticking points are mishandled VAT, wrongly deducted expenses, and tax arbitrage never carried out for lack of time or perspective.

Error 1: forgotten deductible VAT and late-collected VAT#

The director had under-deducted VAT on some purchases (invoices without compliant wording, entry oversights) and, conversely, collected VAT too late on invoiced services. The deductible VAT catch-up was recoverable, but the late-declared collected VAT triggered the 5 % surcharge of art. 1731 of the French Tax Code on sums paid late, on top of late interest.

You will find the basics of VAT in our comparison on keeping your own books as a micro-entrepreneur, even if the logic differs for a company subject to corporate tax.

Error 2: expenses deducted without solid evidence#

Several expenses had been deducted without supporting documents or a demonstrated link to the business. In an audit, these deductions are rejected and the adjustment carries a 40 % surcharge for deliberate breach (Tax Code art. 1729). Here, nothing was bad faith, but the authorities assess case by case, and the line between negligence and deliberate breach is not always clear.

Error 3: tax arbitrage never carried out#

The director paid himself entirely in salary, without ever arbitrating between salary and dividends, nor studying schemes suited to his situation. These are not errors in the legal sense, but a recurring shortfall. That is often where return on fees is decided, through tax support for the director.

The table below reconstructs the order of magnitude of the cost of self-management over the two years concerned. Amounts are illustrative and rounded; they serve to objectify the reasoning, not to promise a result.

Against this right-hand column, the fees of a bookkeeping and presentation mission, spread over the year, generally sit well below the bill of a single year that goes off track. That is the whole point of an honest comparison between a fixed fee or time-based fees.

What tax penalties cover#

1. Late interest. 0.20 % per month, i.e. 2.40 % per year, from the first day of the month after the deadline until payment (Tax Code art. 1727).
2. Failure or late filing. 10 % without formal notice, 40 % if the return is not filed within 30 days of a formal notice (art. 1728).
3. Understated return. 40 % for deliberate breach, 80 % for fraudulent manoeuvres (art. 1729).
4. Late payment. 5 % of sums whose payment was deferred, notably VAT (art. 1731).

These sanctions add to late interest. Conversely, the spontaneous filing of a corrective return, under the right to make a mistake, halves late interest, brought to 0.10 % per month (BOFiP).

Self-management is not a fault in itself, and many directors keep clean books for a while. The problem is not routine entry, which modern tools make easy: it is the lack of a professional eye on the grey areas. VAT on special transactions, borderline deductibility, remuneration arbitrage and year-end close are not guessed in a spreadsheet.

The real cost of going without an accountant is therefore not read in the fees saved, but in the sum of errors invisible until a third party looks at the accounts. A bank, an investor or the tax authorities always end up looking.

The most often overlooked risk is not the penalty, but the moment the error surfaces. A lack of reliable accounting blocks a fundraising, delays a sale, or weakens a banking negotiation at the worst time. At that stage, the clean-up costs more and takes longer than an ongoing mission, because several years must be rebuilt under pressure.

The attestation of accounts, which banks often ask for, expresses moderate assurance on the consistency and plausibility of the accounts (standard NP 2300). Without rigorous upstream bookkeeping, it simply cannot be issued. To place this deliverable properly, see the difference between presenting and keeping the accounts.

The right reflex is not necessarily to outsource everything from day one, but to frame the scope in writing and identify the points beyond your skills.

• Clearly define what you keep yourself and what you entrust (entry, review, filings, close).
• Have at least the VAT and the annual close reviewed by a registered professional.
• Frame the mission in a written engagement letter, reading every line of the quote before signing.
• Anticipate the 2026 deadlines, including mandatory receipt of electronic invoices from 1 September 2026.
• Keep up-to-date books in a reliable tool, which smooths both self-management and collaboration.

To understand the structure of a proposal, our article on reading an accountant's quote details the lines to watch. And for the scope itself, a full accounting engagement or simple bookkeeping and review do not cover the same needs.

The year 2026 adds a factor many self-managed directors underestimate. From 1 September 2026, all businesses liable to VAT must be able to receive electronic invoices in a structured format, with no size condition. Issuing will become mandatory in stages, from 2026 for large companies and mid-caps, then 2027 for SMEs and micro-businesses.

This shift requires configuring a tool able to receive and issue via an approved platform. A director who keeps the books alone in a spreadsheet is not ready for this deadline. The Pennylane software or an equivalent environment, properly set up, becomes a compliance condition, not mere comfort.

There are situations where partial self-management remains reasonable, and others where it becomes a risky bet.

The tipping point is not turnover alone, but tax complexity and stakes. A demanding sector shows it well: we illustrate this in the cost of an accountant in catering.