What is the difference between flat-rate and progressive tax?

The flat-rate system deducts a fixed percentage from your revenue (1% to 2.2%) each month/quarter. The progressive scale applies tax on your revenue after a flat deduction, according to standard brackets. Flat-rate is advantageous if your marginal tax rate exceeds the flat-rate.

When should I fill in the 2042-C-PRO form?

The 2042-C-PRO form is filed each year between April and June, at the same time as your regular income tax return on impots.gouv.fr. You must report your gross annual revenue (before deductions) from the previous year.

Can I change my tax option during the year?

No, the flat-rate option must be chosen before September 30 for the following year. If you're starting your activity, you can opt in during registration or within 3 months of creation. The change takes effect on January 1.

IntermediateTaxRead 20 minUpdated March 2026

Fill the 2042-C-PRO tax form

Each year, you must declare your revenue to the tax office. We show you box by box.

🗂️The 6 key steps

1Log in to impots.gouv.fr in May/June
2Access the supplementary 2042-C-PRO form
3Identify your box: 5KO (sales BIC), 5KP (service BIC), 5HQ (BNC)
4Enter your gross annual revenue (before deduction)
5If flat-rate: fill boxes 5TE/5TB/5TA instead
6Validate and sign your declaration

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Fill the 2042-C-PRO tax form

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Frequently asked questions

What is the difference between flat-rate and progressive tax?

When should I fill in the 2042-C-PRO form?

Can I change my tax option during the year?