Should you bring in an accountant from day one?

Quick answer. A chartered accountant is not mandatory to set up a business, but they become useful as soon as structuring choices arise: legal form, tax regime, director's pay, a forecast for the bank. For a simple sole-trader project you can start on your own; once there is a company, partners or funding, the support often pays for itself through the mistakes it prevents.

You are launching your activity and the same question keeps coming back: should you pay a professional now, or wait until the first set of accounts? The real question is not whether it is mandatory (for most founders it is not), but from what point the advice returns more than it costs. This article settles that trade-off, describes what an accountant actually does at launch, and gives a method to quantify the return on that support.

Legally, no. No rule requires you to use a chartered accountant to register a sole-trader business, a single-member SAS (SASU) or a limited company (SARL). You can file your application yourself on the single window. However, only a professional registered with the Order may keep and review someone else's accounts on a habitual basis: French ordinance no. 45-2138 of 19 September 1945 reserves the practice of the profession and the use of the title to those registered with the Order (art. 3). In other words, you can incorporate on your own, but you cannot have just anyone keep your books.

The real dividing line lies elsewhere. A sole trader with no employee, no VAT and a simple activity can legitimately start without ongoing support. Conversely, as soon as a company, partners, bank funding or committing tax choices appear, the absence of advice often costs you in expensive reversals.

Our reading#

In formation files, the most frequent sticking points are not the registration itself, which has become accessible, but everything around it: a legal form chosen by default, a shaky forecast that sinks the loan, a tax option taken without perspective and hard to undo later. These are exactly the decisions, made once and for several years, that justify a professional eye from the start.

The value is not limited to keeping the books. At the moment of formation, the key issues lie in trade-offs you will not revisit for a long time.

• Choice of legal form and tax regime. SASU, EURL, SARL, SAS or sole trader: each structure carries lasting consequences for tax, social contributions and the director's protection. A poor initial choice can be corrected, but at the price of formalities and sometimes an exit tax cost.
• Director's pay trade-off. Salary, dividends, or a mix: the right split depends on your personal situation, your cash needs and your social cover. This calculation is done beforehand, not afterwards.
• A credible financial forecast. A forecast is not a cosmetic exercise: it is the document that convinces a bank or an investor. It must link revenue assumptions, costs, break-even point and financing plan in a coherent, defensible way.
• Identifying grants and schemes. ACRE, regional schemes, the young innovative company status for R&D projects: these still need to be spotted and their eligibility checked at the right time.
• Setting up the tools. Compliant invoicing, VAT tracking, organising supporting documents, configuring software: these foundations avoid a painful clean-up at the first year-end.

For a full overview of the journey, see also our article on starting your business from A to Z, and our dedicated company formation support service.

The underestimated risk#

The most common trap is not the cost of support, it is the tax or social option taken too quickly. A waiver of the corporate income tax option becomes irrevocable after a certain period; a poorly calibrated VAT regime complicates cash flow in the early months; a badly arbitrated remuneration translates into excess contributions paid for a year before being detected. These mistakes are silent: they trigger no alert, and their cost only surfaces at the first year-end.

The cost of formation support often combines a one-off fee (incorporation, formalities, initial advice) and then recurring fees for bookkeeping and the year-end. Levels vary with the legal form, the volume of entries and the scope entrusted. For detailed orders of magnitude, see our guide on how much a chartered accountant costs in 2026.

Trade-off: go it alone or get support#

Both options are legitimate, and the right choice depends on your project.

• Going it alone suits a simple sole-trader activity, with low volume and few tax stakes. You save the fees, at the price of your time and a risk of error on filings.
• Getting support is justified as soon as a structuring choice, funding or partners come into play. The return is not measured in books kept, but in avoided decisions that would have been costly: the right status, controlled taxation, a forecast that unlocks the loan.

In practice: quantifying the return on investment#

1. List the decisions taken only once (legal form, tax regime, pay, VAT) and estimate the cost of an error on each over three years.
2. Estimate the time you would spend learning and producing your filings yourself, valued at your real hourly rate.
3. Compare this total with the amount of support fees over the same period.
4. Add the value of the schemes captured (grants, exemptions) that you would not have identified alone.
5. Decide: if the cost of avoided errors and time saved exceeds the fees, the support is worthwhile.

This exercise is deliberately cautious: it promises no tax saving and no guaranteed gain. It aims to bring objectivity to a decision often made on instinct.

The best time is before registration, while the choices are still open. Once the company is registered and the first year has started, some decisions are already locked. The three key windows:

• Before formation, to arbitrate the status, tax regime and pay, and to build the forecast.
• At operational launch, to frame invoicing, VAT and tools.
• As the first year-end approaches, at the very least, if you started alone, to secure the close and the options.

For the sector most demanding on timing, our support for tech startups shows clearly why upstream advice changes the outcome of a fundraising round or an innovation scheme.

The young innovative company (JEI) status is a good example of a parameter to check precisely, because its thresholds have changed. For 2026, it requires an SME less than 8 years old devoting at least 20% of its tax-deductible expenses to research and development, this threshold having been raised from 15% to 20% by the 2025 social security financing act. The status grants an exemption from employer social contributions for a period of 7 years. These conditions call for a file-by-file check: a project that targeted eligibility under the old threshold does not keep it automatically.

More broadly, several tax and social parameters shift from one finance act to the next: sole-trader thresholds, VAT exemption, contribution rates. It is precisely because these figures change that up-to-date advice, at the moment of the decision, has value.

A chartered accountant is registered with the Order of Chartered Accountants: that is the baseline guarantee, enforceable and verifiable. Beyond that, look at their experience with files close to yours (your sector, your legal form, your stage), the clarity of the engagement letter and the responsiveness announced. Our guide details the method to choose your accountant.

• An accountant is not mandatory to incorporate, but the practice of the profession is reserved to those registered with the Order (ordinance no. 45-2138 of 19 September 1945, art. 3).
• For a simple sole trader, you can start alone; once there is a company, partners or funding, support is justified.
• The key contributions at launch: choice of status, tax regime, director's pay, a credible forecast, identification of grants.
• The underestimated risk is not the cost, but the tax or social option taken too quickly and hard to correct.
• The return can be quantified: cost of avoided errors plus time saved, compared with the fees, with no promised saving.
• The best time to consult is before registration, while the choices are still open.

• Foreign company with a French subsidiary. VAT compliance, the permanent establishment question and tax treaties make upstream support almost essential.
• Forming with partners. Capital split, governance and clauses are simpler to secure at the start than to fix after a conflict.
• Wealth or holding project. If a holding structure is contemplated, it is better to anticipate it; see our article on setting up a holding and the overview of grants for entrepreneurs.