File correctly,
even in complex cases.
When facing your tax return, you shouldn't have to guess.
RSUs, stock options, LMNP, cross-border workers, capital gains…
Fidencia estimates your tax and tells you what to report, and in which box.
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IFI
LMNP Rental Income
Cross-border (Luxembourg)
Cross-border (Germany)
Cross-border (Switzerland)
Stock Options
Carried Interest
Real Estate Income
Capital Gains
BSPCE
Discover Fidencia
in 30 seconds.
From a complex tax situation to the exact box on your French tax return.
What amount?
to fill in.
on your device.
Understand before you file.
In-depth guides on complex French tax situations — written from the CGI and BOFiP. Available in French only.
Franco-Swiss cross-border workers
Two conventions, two tax logics depending on the Swiss canton. 1983 Agreement vs 1966 Convention, withholding tax, remote work.
Real estateLMNP furnished rentals 2026
Micro-BIC or actual expenses: which to choose? Depreciation, Loi Le Meur thresholds, impact on your net tax burden.
InvestmentCapital gains on securities
Flat tax 30% or progressive scale? Allowances, losses, PEA, brokerage accounts: the 2026 French tax rules.
Real estateIFI — Wealth Tax 2026
Are you liable? Taxable assets, exclusions, deductible debts, 2042-IFI filing.
All simulators.
One subscription.
Access all Fidencia simulators and annual updates incorporating new tax legislation.
- ✓ Unlimited access to all simulators
- ✓ Automatic annual tax updates
- ✓ PDF summary with boxes to fill in
- ✓ History of your calculations
Built for rigour
Tax return boxes identified
Each result tells you exactly which box in your tax return to report each calculated amount.
Data stays on your device
No calculation ever leaves your browser. Your financial data remains private — never transmitted to third parties.
Updated with each Finance Act
Tax scales, allowances and thresholds recalculated each year as soon as the Finance Act is published.