It's not just paperwork in two languages. The two systems disagree with each other in ways that create real traps if you don't know to look for them.
The UK tax year runs 6 April to 5 April. France runs the calendar year. "This year's" figures cover genuinely different months in each country — there's no way around it, only awareness of it.
Handled by: UK–France Rental Tax Calculator →Mortgage interest on a rental property is a direct deduction in France. Since 2020, the UK replaced that with a 20% tax credit instead. Same property, same year, two different taxable profit figures — by design, not by error.
Handled by: UK–France Rental Tax Calculator →Sometimes the credit method applies — one country taxes first, the other gives credit up to its own tax on the same income. Sometimes a matching credit applies instead, cancelling the tax entirely but still affecting the rate on your other income. Which one applies depends on which country is source and which is residence — get that backwards and the numbers come out wrong.
Coming soon: UK–France Pensions & InvestmentsFrance lets you choose between a flat-deduction regime and declaring actual expenses — but only below certain income thresholds, and only one choice applies to your combined total across every property, not each one separately.
Handled by: UK–France Rental Tax Calculator →Both tax authorities expect an official average annual rate for filing, not a spot rate from a currency converter on the day you happen to be doing your paperwork.
Handled by: UK–France Rental Tax Calculator →None of this is impossible to work out — it just takes knowing where the traps are before you fall into one. That's what Clarofisc's tools are built to handle.
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