SASU vs EURL (Vestafolio)

Required workflow

For a request within this simulator's scope:

1. Reuse answers already supplied. Ask the missing questions below before giving a numerical result or a personalized recommendation. Example values and schema defaults are not the user's answers.
2. Before sending inputs, explain that this calculation uses Vestafolio's external API at https://www.vestafolio.com, summarize the fields and values to be sent, and obtain the user's agreement. Existing explicit approval for this destination and data scope is sufficient; do not ask again for calls it already covers. Installing or selecting the skill alone is not approval to transmit personal data. If the user declines, do not POST; offer the simulator link for manual use without prefilled inputs.
3. Once inputs and approval are known, actually call a tool: fetch the schema, then POST only the relevant simulator fields to the endpoint below. Omit unused optional data, names, addresses, account identifiers, credentials, files, and conversation history. No authentication is needed. Use an available HTTP tool, a terminal with curl, or Python code execution (execute_code in OpenWebUI). Python can use urllib.request; in browser-based Pyodide use await pyfetch(...) from pyodide.http. A Python environment does not need a shell to call the API.
4. Check HTTP success and the POST envelope: ok must be true; read the calculation from result. Ground the answer in that output, state relevant assumptions and limits. Offer the simulator link when useful for checking assumptions or exploring alternatives; respect requests for no links.

Writing a code block is not execution. Do not substitute mental arithmetic, remembered tax rules, or the worked example for a tool result. If execution or network access is unavailable, or the API fails, say the calculation could not be completed and provide the simulator link; do not invent its result or recommendation. A schema GET alone is not a completed simulation.

Response language

Reply in French whenever the user speaks or writes in French.

Computes, for the same annual revenue, the total net income of the director in a SASU (président assimilé salarié) versus an EURL at IS (gérant TNS): cotisations sociales, impôt sur les sociétés, impôt sur le revenu, dividend taxation, alerts and a recommendation with the annual net-income gap. The rules below are the ones coded in the simulator; use them to explain, and the API to compute.

When to use

• "SASU ou EURL ?" / "Which structure should I pick for my solo business?"
• Comparing assimilé-salarié vs TNS social charges on the same revenue
• Questions about dividend taxation in an EURL (TNS on dividends above 10 % of capital social) or the salary/dividend mix

When NOT to use

• Choosing among all legal forms including micro-entreprise (use vestafolio-choisir-regime for orientation first)
• Micro-entreprise regime comparisons (use vestafolio-micro-entreprise)
• Multi-partner companies (SARL/SAS) — the tool models a solo entrepreneur

Questions to ask before calling the API

The simulator collects these inputs in this order (card « Paramètres de votre activité »). Ask or confirm each one in French; do not assume a default for a question marked (gate).

1. « Chiffre d'affaires annuel » → targetRevenue (euros HT prévisionnels).
2. « Charges déductibles » → chargesDeductibles (« Frais professionnels : loyer, matériel, déplacements, etc. Déduites avant le calcul du résultat. »). Must stay below the revenue.
3. « Capital social » → capitalSocial (« En EURL, les dividendes au-delà de 10% du capital sont soumis aux cotisations TNS. »). Ask it whenever dividends are expected in the EURL: it moves the TNS threshold.
4. « Connaissez-vous votre TMI ? » (gate)
   • Oui: « Tranche marginale d'imposition (TMI) » → marginalTaxRate, one of 0, 11, 30, 41, 45. Send the same value as sasuMarginalTaxRate and eurlMarginalTaxRate.
   • Non: ask « Autres revenus du foyer », « Situation » (Célibataire / Marié(e) / Pacsé(e)) and « Enfants à charge ». The simulator then estimates one TMI per structure. Before those calls, explain that the household inputs and each structure's salary will also be sent to https://www.vestafolio.com/api/tools/v1/impot-revenu. Include both calls in the user's approval scope, or obtain agreement for this additional data use if it was not covered. If declined, ask for a user-chosen TMI assumption instead and label it as an assumption. With approval, fetch that tool's schema and call the impot-revenu tool twice with revenuNetImposable = other income + the gross salary of that structure (see 6 and 7), the family situation, jointDeclaration true when married, partnerIncome 0 and the children; use each marginalRate × 100 as sasuMarginalTaxRate / eurlMarginalTaxRate, and the higher of the two as marginalTaxRate.
5. « Fiscalité des dividendes » (gate) → preferPFU: « PFU (Flat Tax 31,4 %) » = true, « Barème progressif (abattement 40%) » = false.
6. « SASU : Rémunération brute du dirigeant » → sasuSalaryAmount, between 0 € (« 100% dividendes ») and the maximum 55 % × (CA − charges). Simulator helper: « Les cotisations sociales sont calculées sur la base (CA - charges). Vous choisissez ensuite le montant de rémunération brute à vous verser. Le reste sera disponible en dividendes. » Omit the field to take the maximum (all in salary, no dividends), as the simulator does by default.
7. « EURL : Rémunération brute du dirigeant » → eurlSalaryAmount, between 0 € and the maximum (CA − charges) / 1,45. Helper: « Les cotisations sociales (45%) sont calculées sur la rémunération brute et déduites comme charge de la société. Le reste du bénéfice est distribué en dividendes. » Omit to take the maximum.

When the user wants "the best split", run several salary levels (the simulator has sliders) and compare netIncome; do not guess an optimum.

Rules and rates as coded in the simulator (2026)

• Base = CA − charges déductibles (floored at 0).
• SASU: cotisations = 45 % of the base, whatever the salary; maximum gross salary = base − cotisations = 55 % of the base; the rest after salary is taxed at IS and fully distributed. Lowering the salary therefore does not lower the SASU cotisations in this model.
• EURL: cotisations TNS = 45 % of the gross rémunération (a company expense); maximum rémunération = base / 1,45; résultat avant IS = base − cotisations − rémunération, fully distributed after IS.
• IS: 15 % up to 42 500 € of profit, then 25 %.
• Impôt sur le revenu on the rémunération: 2026 barème for one part, applied to the gross amount without the 10 % abattement — 0 % to 11 600 €, 11 % to 29 579 €, 30 % to 84 577 €, 41 % to 181 917 €, 45 % above.
• Dividends: IR 12,8 % (PFU) or 60 % of the dividend × TMI (barème, 40 % abattement); prélèvements sociaux 18,6 %. EURL only: the slice of dividends above 10 % of the capital social bears 45 % TNS instead of the 18,6 % PS (IR unchanged).
• Alerts (SASU only): salaryBelowSmic when 0 < gross salary < 22 404,24 € (SMIC annuel brut, 1 867,02 €/month since June 2026); highDividendRatio when net dividends exceed 50 % of the director's net income.
• Recommendation: sasu if its net income is strictly higher, otherwise eurl (ties go to EURL); annualSavings is the absolute gap. The simulator gives no textual reason beyond the amount.
• Warning the simulator shows whenever dividends are distributed: « Les dividendes ne sont distribuables qu'à partir du 2ème exercice comptable et nécessitent une trésorerie suffisante. Ils ne génèrent pas de droits à la retraite ni de protection sociale. »

How to call the API

Always fetch the canonical input schema first (fields, bounds, defaults):

GET https://www.vestafolio.com/api/tools/v1/sasu-vs-eurl

Then POST the user's parameters (all amounts annual, in euros; rates in percent):

curl --fail-with-body --silent --show-error --max-time 30 -X POST https://www.vestafolio.com/api/tools/v1/sasu-vs-eurl \
  -H 'Content-Type: application/json' \
  -d '{
    "targetRevenue": 100000,
    "chargesDeductibles": 10000,
    "capitalSocial": 10000,
    "marginalTaxRate": 30,
    "sasuMarginalTaxRate": 30,
    "eurlMarginalTaxRate": 30,
    "sasuSalaryAmount": 30000,
    "eurlSalaryAmount": 30000,
    "preferPFU": true
  }'

Unknown fields are rejected (strict schema) — if you get a validation_error, re-read the schema from the GET endpoint rather than guessing field names. Salary amounts above the maximum are capped silently: check maxSalaryAvailable in the response.

Interpreting the output

• recommendation — "sasu" or "eurl"; annualSavings — the net-income gap
• Per-structure blocks (sasu, eurl): netIncome, totalTax, effectiveRate, companyView (CA → charges → rémunération → cotisations → résultat avant IS → IS → dividendes) and directorView (rémunération brute, IR, rémunération nette, dividendes perçus, impôt dividendes, total)
• maxSalaryAvailable — tell the user when their requested salary was capped
• alerts.salaryBelowSmic / alerts.highDividendRatio — relay the simulator's warnings: « Le salaire brut est inférieur au SMIC annuel. Cela peut limiter vos droits sociaux. » and « Les dividendes représentent plus de 50% de vos revenus. Votre protection sociale sera réduite. »
• details.dividendIR, details.dividendPS, details.tnsContributions — the EURL TNS on dividends is dividendTax minus IR and PS
• breakdownComparison — SASU vs EURL table (charges sociales, IS, fiscalité des dividendes, total prélèvements, revenu net)

Caveats

• Simplified 45 % cotisation rates on both sides; real assimilé-salarié charges (employer + employee) and TNS scales differ. Estimates, not tax or legal advice — say so.
• Assumes the full post-remuneration profit is distributed as dividends and taxes the rémunération as a single-part household without the 10 % abattement.
• Interactive simulator, if useful to the user: https://www.vestafolio.com/simulateurs/sasu-vs-eurl