Impôt sur la plus-value immobilière (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 the tax due on a French property sale: gross and net capital gain, acquisition-fee and renovation deductions, holding-period abatements, IR at 19 %, prélèvements sociaux at 17,2 %, the high-gain surtax, exemptions, and the savings from postponing the sale by one year. The rules below are the ones coded in the simulator; use them to explain, and the API to compute.

When to use

• "Combien d'impôt sur ma plus-value immobilière ?" / "How much tax if I sell my French property?"
• Questions about the abattement pour durée de détention, or the 22-year (IR) and 30-year (PS) exemptions
• Selling a résidence secondaire, a rental, or an LMNP au régime réel (amortization reintegration since 2025)
• "Should I sell now or wait a year?" decisions

When NOT to use

• Capital gains on securities/shares (PFU territory — not this simulator)
• Professional sellers or companies at IS (only particulier and SCI à l'IR are modeled)
• Non-French property or non-French tax situations

Questions to ask before calling the API

The simulator asks these inputs, in this order (card « Paramètres de la vente »). Ask or confirm each in French; stop early when a gate makes the rest irrelevant.

1. « Prix d'achat » → purchasePrice and « Prix de vente » → salePrice.
2. « Date d'achat » → purchaseDate and « Date de vente » → saleDate (YYYY-MM-DD; the sale must be after the purchase; the site defaults the sale to today). The holding period is derived from them in whole years (the day of the month is ignored).
3. « Résidence principale » (gate) → isMainResidence (« Exonération totale si oui »). If Oui, the sale is fully exempt: send the flag and skip the remaining questions.
4. Only if Non: « Investissement locatif » (gate) → isRentalInvestment (« Active le traitement spécifique LMNP lors de la revente »). Only if Oui: « Régime réel » (gate) → isRealRegime (« Si non, le calcul standard de plus-value s'applique »). Only if Oui: « Somme totale des amortissements à date » → totalAmortization (« En LMNP au réel, la totalité des amortissements déjà déduits est réintégrée dans la plus-value brute. »); the site requires an amount strictly above 0.
5. Only when the gross gain is positive — « Frais déductibles »: « Frais d'acquisition » → acquisitionFeesMethod: « Forfait 7.5% » = forfait, « Montant réel » = reel (then acquisitionFeesReal, the documented amount), « Aucun » = none. « Travaux » → renovationMethod: « Forfait 15% » = forfait (only available from 5 full years of holding; otherwise it yields 0), « Montant réel (justificatifs) » = reel (then renovationReal), « Aucun » = none.
6. sellerType: the website always uses particulier; the API also accepts sci_ir, which follows the same rules. Send particulier unless the user sells through a SCI à l'IR.

Rules and rates as coded in the simulator (2025-2026)

• Standard case: net gain = sale price − purchase price − acquisition fees (7,5 % forfait or documented) − works (15 % forfait from 5 years, or documented), floored at 0.
• LMNP au régime réel (isRentalInvestment and isRealRegime): acquisition fees are added to the acquisition price instead of being deducted, the works are subtracted from the sale price only from 5 years of holding, and the amortization deducted during the rental is added back to the gain.
• Abattement IR: 6 % per year from the 6th to the 21st year, 4 % for the 22nd, so full exemption at 22 years. Abattement PS: 1,65 % per year from the 6th to the 21st year, 1,60 % for the 22nd, 9 % per year from the 23rd to the 30th, full exemption at 30 years.
• Tax: 19 % IR on the gain after the IR abatement, 17,2 % PS on the gain after the PS abatement, plus the surtax on the IR base above 50 000 € (2 % to 6 % by bands, with smoothing at each band entry).
• Full exemptions: résidence principale, sale price ≤ 15 000 €, holding of 30 years or more. From 22 years the IR is exempt and only PS remain.
• savingsIfWait1Year = current tax − tax if the sale happened one year later (the site suggests waiting when it exceeds 100 €).

How to call the API

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

GET https://www.vestafolio.com/api/tools/v1/impot-plus-value

Then POST the user's parameters (amounts in euros, dates as YYYY-MM-DD strings — saleDate must be after purchaseDate):

curl --fail-with-body --silent --show-error --max-time 30 -X POST https://www.vestafolio.com/api/tools/v1/impot-plus-value \
  -H 'Content-Type: application/json' \
  -d '{
    "purchasePrice": 200000,
    "salePrice": 280000,
    "purchaseDate": "2015-01-01",
    "saleDate": "2026-06-01",
    "isMainResidence": false,
    "isRentalInvestment": true,
    "isRealRegime": true,
    "totalAmortization": 45000,
    "acquisitionFeesMethod": "forfait",
    "renovationMethod": "reel",
    "renovationReal": 20000,
    "sellerType": "particulier"
  }'

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. acquisitionFeesReal / renovationReal are required with the reel methods.

Interpreting the output

• totalTax — the key decision figure (IR + PS + surtax); netProceeds is the gain kept after tax, effectiveTaxRate the levy on the gross gain
• grossCapitalGain vs netCapitalGain — before/after acquisition-fee and renovation deductions; in LMNP réel also transferProceeds, acquisitionPriceUsed (« Prix d'acquisition corrigé ») and amortizationReintegration
• irAbatementRate / psAbatementRate and the corresponding amounts — how the holding period shrank the taxable base; holdingPeriodYears / holdingPeriodMonths
• yearsUntilIRExemption / yearsUntilPSExemption and savingsIfWait1Year — highlight these for "sell now or wait" questions
• abatementSchedule — the full 0-to-30-year abatement table by holding duration
• exemptions / isFullyExempt — applicable exemption reasons (French labels)

Caveats

• Rules as coded for 2025-2026; rates and abatement schedules change with finance laws. Estimates, not tax advice — say so.
• The forfait options (7,5 % fees, 15 % works) are simulator conventions the user may or may not be entitled to; actual documented amounts can differ.
• Interactive simulator, if useful to the user: https://www.vestafolio.com/simulateurs/impot-plus-value