Specialist accountant for French maîtres d'œuvre: Loi MOP billing, decennial insurance accounting, subcontractor management, VAT on intellectual services, progress billing. Hayot Expertise Paris.
A maître d'œuvre (MOE) — French construction project manager — holds a uniquely demanding position in the building chain: they design the project (engineering studies), coordinate contractors (direction of works) and carry ten-year decennial liability for every structure they deliver. This triple responsibility — intellectual design, on-site coordination and long-tail legal liability — produces an accounting and tax profile that few generalist accountants fully master.
First specificity: progress billing under the Loi MOP. When an MOE works on a public contract (hospital, school, public building), fees follow the mission phases set by the Loi MOP of 12 July 1985 (public construction project management) and its implementing decree of 29 November 1993. Each phase (ESQ, APS, APD, PRO, ACT, EXE, DET, OPC, AOR) is invoiced separately at a defined stage of completion. Recognising these staggered fees correctly — in step with the real progress of studies and works — is essential to a faithful set of accounts.
Second specificity: VAT on works and on fees. The MOE charges their own fees at the standard 20% VAT rate (intellectual services). But they also supervise contractor invoices paid by the client: when the MOE acts as a delegated client, they can be involved in managing VAT flows (reverse-charge on construction subcontracting, reduced 5.5% or 10% VAT on energy-renovation works). The boundary between pure advisory missions (20%) and missions that include equipment supply or works (potentially reduced rates) must be drawn precisely.
Third specificity: decennial liability insurance and professional civil liability. Every MOE must hold a decennial professional civil liability policy covering accepted works for 10 years. The annual premium — often €2,000 to €20,000 depending on turnover and project types — is fully deductible. Its annual recognition (sometimes spread as a prepaid expense when a single premium covers more than one financial year) is a faithful-view issue.
Fourth specificity: subcontracting and partner fee notes. MOEs frequently rely on freelance collaborators or specialist subcontractors (structural engineering, MEP engineering, quantity surveyors, surveyors). These fee rebates are deductible from the MOE's profit but must be correctly qualified (genuine subcontracting versus disguised employment) to avoid tax or social-security reclassification.
A specialist accountant delivers direct value on these four fronts: Loi MOP compliance and progress billing, VAT optimisation, decennial insurance handling and subcontracting structure.
The Loi MOP defines nine mission phases for the design and construction supervision of a public-sector building:
| Phase | Acronym | Content | Typical % of fees |
|---|---|---|---|
| Preliminary studies | EP/ESQ | Feasibility, sketch | 4-8% |
| Outline design | APS | Technical programme definition | 8-12% |
| Detailed design | APD | Detailed cost estimate | 10-15% |
| Project | PRO | Full technical documents | 15-20% |
| Tendering assistance | ACT | Tender docs, bid analysis | 5-8% |
| Construction studies | EXE | Execution drawings, coordination | 12-18% |
| Construction supervision | DET | Site supervision, drawing approvals | 15-25% |
| Site coordination | OPC | Programming, site meetings | 5-10% |
| Acceptance assistance | AOR | Handover, snag-list clearance | 3-5% |
Each phase is invoiced when complete or on a schedule defined in the contract. Percentage-of-completion accounting (FAE / TEC method — accrued revenue and work in progress) is mandatory to give a faithful view of profit, particularly for MOEs running several projects at different stages of completion in parallel.
For private contracts, fee structuring is more flexible (lump-sum, firm + conditional tranches), but the progress-billing principle remains the best practice.
VAT on MOE fees: maître d'œuvre fees are intellectual services subject to 20% VAT, whether the project is new build, renovation, or works for a private individual.
Exception — reduced VAT on certain bundled missions: if the MOE delivers a full-scope mission including energy renovation works on a dwelling more than two years old, and the mission includes both design and the supply and installation of eligible equipment (insulation, boiler, heat pump), reduced VAT (10% or 5.5% depending on the equipment) may apply to the works portion. This hybrid invoice (20% services + reduced-rate works) requires detailed and rigorous billing.
VAT reverse-charge (autoliquidation): when the MOE subcontracts works to construction firms that invoice under reverse-charge (mandatory for BTP subcontractors of a principal contractor), the MOE declares the VAT on behalf of the subcontractor on their own VAT return. This mechanism is a frequent source of errors (VAT declared but not remitted, or the opposite).
VAT chargeable event: like for engineering firms, MOE fees fall under VAT on debits by default. Opting for VAT on receipts (cash-basis VAT) can free up significant cash when payment terms are long (public contracts: 30-day legal cap, but practical delays are common).
The MOE's decennial insurance covers their liability for 10 years after acceptance. Correct accounting matters:
In 2026, decennial premiums in the MOE sector are up 8-15%, reflecting higher loss ratios (energy diagnostics, retrofits, new construction techniques). This increase directly impacts profitability and must be anticipated in the budget.
The maître d'œuvre can operate under several structures:
Sole practice (BNC, return 2035): suited to individual MOEs without employees or with very few collaborators. Pros: simplicity, no IS filing, TNS (self-employed) social charges (lower for moderate income). Cons: unlimited liability on personal assets, no goodwill amortisation.
EURL or SARL under corporate tax (IS): recommended once profit exceeds €60,000-80,000. IS (15% up to €42,500, then 25%) combined with optimised director compensation lowers the total tax burden. Liability is capped at contributions.
SAS or SASU: recommended when the MOE plans to bring in partners (equity entry), raise funds, or build a multi-office firm. The "assimilated-employee" status of the president provides broader social cover (including unemployment, unlike TNS managers). BSPCE share warrants can lock in key collaborators.
SELARL or SEL: some MOEs operate via sociétés d'exercice libéral (liberal-profession companies) to combine liberal-profession status with corporate tax. Less common and more complex to administer.
Our firm runs an annual comparative simulation for every client to identify the optimal regime as turnover and profit evolve.
The cash flow of a maître d'œuvre practice is subject to recurring pressures:
We build a monthly forecast cash plan integrating the billing pipeline (open missions × completion × remaining fees), major scheduled outflows (insurance, social charges, IS instalments) and subcontracting flows.
For MOEs employing collaborators (architect-assistants, quantity surveyors, draftspeople), we run payroll under the applicable collective bargaining agreement (Syntec for engineering firms, or the Architecture CBA for MOEs in architectural agencies):
We support new maîtres d'œuvre in setting up their practice:
| KPI | Formula | MOE target |
|---|---|---|
| Fee ratio to works cost | Net fees / Total net works cost | 6-12% |
| Billing rate | FAE + invoices issued / Works delivered | > 90% monthly |
| Client days-sales-outstanding | (Receivables / Turnover) × 365 | < 60 days |
| Subcontracting ratio | Subcontracted fees / Net fees | 15-40% |
| Operating margin | EBITDA / Net turnover | 20-35% (liberal), 15-25% (IS) |
| Decennial insurance ratio | Annual premium / Net turnover | < 3% (target) |
| Billable utilisation | Billable hours / Available hours | > 80% |
Situation: Mr Faure, independent maître d'œuvre under BNC for 8 years, €220,000 net turnover, BNC profit €95,000, marginal tax rate 41%. No employees, three regular subcontractors (structural engineering, quantity surveyor, surveyor). Decennial insurance (€14,000/year) and CIPAV/URSSAF social charges (€32,000/year) absorb a large share of income. Mr Faure handles a mix of public and private contracts.
Issues identified by our firm:
Actions taken:
Total annual tax and social savings: ~€22,000.
For an MOE working with public clients paying at 30-60 days (sometimes 90), staying on debit-basis VAT means pre-financing the VAT. Switching to cash-basis VAT is straightforward and can release €10,000-€20,000 of cash in the first year.
If the premium partly covers the following year (annual premium paid in July → 5 months on the next financial year), the current-year charge must be prorated. Otherwise, profit is artificially reduced by a charge belonging to year N+1.
On public contracts, subcontractors must be declared and accepted by the client (Subcontracting Act of 31 December 1975). An undeclared subcontractor cannot benefit from direct payment, and the MOE remains solely liable for unpaid invoices. Our firm checks contractual compliance at the start of every new project.
Underpricing the APS/APD/PRO phases (often to secure the contract) translates into negative profitability in the DET/AOR phases (site supervision), which are the most time-consuming. Phase-by-phase forecasting flags structurally loss-making missions before signature.
A decennial claim being processed (reported defects, ongoing expertises) should be provisioned if the excess or part of the repair costs may fall on the MOE. Ignoring this provision leads to an unpleasant surprise on settlement.
Our firm has been supporting independent maîtres d'œuvre and MOE companies for over 10 years. We master Loi MOP, VAT on MOE services, decennial insurance and the accounting management of long-tail contracts. We deliver tailored engagements suited to your activity (a few public contracts per year as a sole practitioner, or a multi-collaborator IS firm). Free quote within 24 hours — first meeting on the house.
The French maîtrise d'œuvre sector counts roughly 4,000 practices represented by UNTEC (the National Union of Construction Economists and Coordinators) plus several thousand architect-led MOEs. The sector handles about €5 billion of contracts each year, with strong dependence on the public sector (local authorities, hospitals, schools). The Loi MOP governs missions on public projects. Higher decennial loss ratios, construction-cost inflation (+15-20% from 2021 to 2025) and the RE2020 thermal regulation are creating new accounting and liability challenges.
Do not book only issued invoices: record FAE (accrued revenue) entries for studies completed but not yet invoiced, and provision for losses on completion as soon as an overrun appears. This rigour gives a faithful view of profitability period by period.
If your clients (public or private) pay at 30-90 days, electing cash-basis VAT aligns your collected VAT with actual receipts. It can release €10,000-€20,000 of cash in the first year of the switch.
Your decennial premium is 100% deductible. If a single premium covers several months, prorate the deduction across the matching periods (prepaid expense for the share belonging to the following year). Keep every insurance certificate — they will be requested in a tax audit.
Every subcontractor must be declared to and accepted by the public client. Undeclared subcontractors cannot claim direct payment and you remain solely liable for unpaid invoices. Build a subcontractor-declaration checklist into your project-start process.
Under BNC, social contributions (URSSAF, CIPAV) and income tax are calculated on the prior year's profit and adjusted in year N+1. Set aside 30-35% of your monthly profit each month to avoid surprises. Under IS, quarterly instalments are predictable — include them in your cash plan.
At that level, the BNC marginal tax rate reaches 41% plus social charges, i.e. a 55-60% total burden on the last euro. Switching to an IS company (SASU or SARL) with a salary + dividends mix brings the total burden down to 45-50%, saving €5,000-€10,000 a year. We run a free comparative simulation on request.
Wherever you are in France, we deploy a 100% digital interface to deliver fast, highly-structured accounting and financial steering.
Samuel Hayot is a French chartered accountant and statutory auditor registered with the Paris professional bodies.
The firm is based in Paris 8 and operates with a delivery model designed for businesses located across France.
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30 complimentary minutes with Samuel Hayot to challenge your reporting and surface your priority levers.
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The main accounting difference is the maître d'œuvre's decennial liability, which requires a dedicated insurance policy and rigorous accounting treatment (annual premium, provisions for claims in progress). On the mission side, the MOE also handles construction supervision (DET), which means longer site monitoring and billing over a more extended period than a BET's pure design work. Both activities share progress billing and the management of FAE / TEC entries.
Under the Loi MOP, MOE fees for public contracts are split into 9 mission phases (ESQ, APS, APD, PRO, ACT, EXE, DET, OPC, AOR), each invoiced on completion. Total fees are set as a percentage of the estimated works cost (typically 6-12%). Revenue recognition follows the percentage-of-completion method: work done but not yet invoiced is recorded as 'factures à établir' (accrued revenue) at each month-end close.
Yes — at the standard 20% rate. MOE fees are intellectual services subject to standard VAT on both public and private contracts, on new builds and on renovations. Partial exception: if the MOE delivers a turnkey mission including energy renovation works on a dwelling more than two years old (supply and installation of eligible equipment for a private homeowner), the works portion can fall under reduced VAT (10% or 5.5%). Opting for cash-basis VAT (rather than debit-basis) is particularly useful for MOEs with slow-paying public clients.
The main optimisation levers are: (1) choice of structure — BNC suits profits up to about €70,000-€80,000, IS via SARL or SAS beyond that; (2) salary + dividend mix for company directors; (3) deductible PER (retirement savings plan), available to both TNS and employee directors; (4) full deduction of decennial insurance, site-visit travel and professional equipment; (5) electing cash-basis VAT to free cash on public contracts with long payment delays.
Yes, decennial liability insurance premiums are fully tax-deductible for a maître d'œuvre, whether operating as a BNC professional or through a limited company (SARL/SAS). If the premium covers multiple accounting periods (e.g., annual premium paid mid-year), only the portion relating to the current financial year is deducted — the rest is deferred as a prepaid expense.
The transition from BNC (individual practice, 2035 return) to a limited company under corporate tax (SARL or SAS) becomes financially advantageous when annual profit exceeds approximately €70,000-80,000. At that level, combined income tax and social charges on BNC income reach 55-60% of the marginal euro, while a company structure with optimised salary + dividends typically reduces the total burden to 45-50%, saving €5,000-15,000/year.
The legal payment term on public-sector contracts is 30 days from invoice receipt. Beyond that, statutory late-payment interest applies automatically (ECB rate + 8 points, approximately 8.9% in 2026) along with a flat €40 indemnity per overdue invoice. This interest is due by law without prior formal notice. Our firm builds the calculation of statutory interest into our receivables monitoring and prepares the corresponding claims on your behalf.
Chartered Accountant, registered with the Institute of Chartered Accountants.
Regulated French accounting and audit firm based in Paris 8, built to support companies across France with a digital and decision-oriented approach.