About Fidencia

So that filing your tax return
is no longer a guessing game.

RSUs, LMNP rental income, cross-border work? The official tax return notice doesn't tell you which box to use. Fidencia does.

Our approach

The real problem isn't calculating. It's knowing what goes where.

Every year, thousands of taxpayers face situations their tax software doesn't handle: RSU vesting, stock option exercises, foreign-source income, furnished rentals, capital gains. The official notice isn't enough.

Fidencia was built around a simple observation: there was no guide that, for each complex situation, told you exactly which box to fill, with which amount, and why. The tax estimate is there to help you understand the figure. The point is not to put it in the wrong box.

Each module is built directly from the Code Général des Impôts (CGI) and BOFiP doctrine. Tax thresholds and rates are updated with each Finance Act.

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Box by box

For each situation, Fidencia tells you exactly which box on your tax return to fill and what amount to report.

Official sources

CGI, BOFiP, Légifrance, DGFiP documentation. Every parameter is documented and traceable.

Detailed breakdown

Every result is broken down line by line: taxable base, allowance, rate, social contributions.

Annual updates

Tax parameters are updated each year following the publication of the Finance Act.

What Fidencia does — and does not do

What Fidencia does

  • Tells you box by box what to report in your French tax return
  • Covers 10 complex tax situations the official notice doesn't explain
  • Estimates income tax according to current official French tax schedules
  • Calculates social contributions, CEHR, and statutory allowances
  • Applies bilateral tax treaties (Switzerland, Luxembourg, Germany)
  • Updates parameters after each Finance Act

What Fidencia does not do

  • Is not a tax consultancy or legal advisory firm
  • Does not consider your overall financial or asset situation
  • Does not cover situations outside its modules (structures, succession, groups)
  • Does not guarantee accuracy in atypical or mixed situations
  • Does not replace an accountant or tax lawyer
  • Does not produce documents that can be submitted to tax authorities
11 modules available

Situations covered

Note: all modules are in French, as they cover French tax law exclusively.

EmployeeFree Shares (RSUs)CGI art. 80 quaterdecies
EmployeeStock OptionsCGI art. 80 bis / 163 bis C
StartupBSPCECGI art. 163 bis G
InvestmentCapital GainsCGI art. 150-0 A
Real estateLMNP Furnished RentalCGI art. 35 bis / BIC
Real estateReal Estate IncomeCGI art. 14 à 33 quinquies
Real estateIFI — Wealth TaxCGI art. 964–983
Cross-borderCross-border — SwitzerlandFranco-Swiss treaty 1966
Cross-borderCross-border — LuxembourgFranco-Luxembourg treaty 1958
Cross-borderCross-border — GermanyFranco-German treaty 1959
Private equityCarried InterestCGI art. 150-0 A / 163 quinquies C
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Important disclaimer

The information provided by Fidencia is indicative only. It does not constitute tax, accounting or legal advice. Fidencia accepts no liability for decisions made on the basis of this information without prior validation by a qualified professional (accountant, tax lawyer).

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