Tax & Charges14 June 2026· 7 min read

Declaring Your Micro-Enterprise Income (2042-C-PRO)

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Updated 30 June 2026
Declaring Your Micro-Enterprise Income (2042-C-PRO)
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Declaring Your Micro-Enterprise Income (2042-C-PRO)

The micro-entrepreneur has two distinct appointments with the administration: the revenue declaration to URSSAF (monthly or quarterly, for social contributions) and the annual income declaration for tax (in spring). This second step goes through form 2042-C-PRO. Here is how to complete it without mistakes.

Two declarations not to confuse

This is a frequent confusion among beginners. You declare your revenue twice, but for different purposes:

DeclarationWhereWhyWhen
URSSAF revenueautoentrepreneur.urssaf.frCalculate social contributionsMonthly or quarterly
2042-C-PROimpots.gouv.frCalculate income taxOnce a year, in spring

The income declaration does not recalculate your contributions: it only serves to establish your tax. For the social part, see monthly or quarterly URSSAF declaration.

What you report on form 2042-C-PRO

On form 2042-C-PRO, you do not indicate a profit, but your gross annual revenue, in the box corresponding to your activity:

  • Sale of goods (BIC);
  • Services (BIC);
  • Liberal professions (BNC).

The administration automatically applies the flat allowance (71% for sales, 50% for BIC services, 34% for BNC) to determine your taxable income. You therefore do not have to calculate the allowance yourself: simply report the gross revenue collected.

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The case of the flat-rate income tax

If you opted for the flat-rate income tax (paid alongside your URSSAF contributions), you have already settled your tax on this income. You must still report your revenue in the boxes dedicated to the flat-rate income tax on form 2042-C-PRO.

Why? Because this income, even already taxed, enters the calculation of your reference tax income and your household's tax rate (effective-rate rule). Not declaring it would distort your overall tax situation. To understand the flat-rate income tax trade-off, see micro-enterprise charges.

The concrete steps

1. Log in to your account on impots.gouv.fr.

2. Tick the supplementary declaration (2042-C-PRO) among the proposed sections.

3. Report your annual revenue in the right box (BIC sales, BIC services or BNC), depending on whether you are on the flat-rate income tax or not.

4. Check the carry-over of any other household income.

5. Validate: the administration calculates the tax by applying the allowance.

Mistakes to avoid

  • Confusing revenue and profit: on form 2042-C-PRO, you declare gross revenue, not net after contributions.
  • Forgetting to declare under the flat-rate income tax: the revenue must still appear for the rate calculation.
  • Choosing the wrong category (BIC/BNC): the allowance depends on the nature of the activity.
  • Duplicating with URSSAF: the income declaration does not replace the URSSAF revenue declaration, and vice versa.

Key takeaway: on form 2042-C-PRO, always declare your gross revenue, never an already-reduced profit. The allowance is applied by the administration.

Once the tax is established, it is collected via pay-as-you-earn as instalments, unless you opt for the flat-rate income tax. Discover this mechanism in our guide to pay-as-you-earn for the self-employed, and estimate your taxation with the micro-enterprise simulator.

Frequently asked questions

Do you declare your revenue to both URSSAF and the tax office?
Yes, these are two distinct declarations. The URSSAF declaration (monthly or quarterly) serves to calculate social contributions; the annual declaration on form 2042-C-PRO serves to calculate income tax. One does not replace the other.
What do you declare on form 2042-C-PRO: revenue or profit?
You declare gross annual revenue collected, not a profit. The administration then automatically applies the flat allowance (71%, 50% or 34% depending on the activity) to determine the taxable income.
Do you declare your revenue even with the flat-rate income tax?
Yes. Even if the tax has already been paid via the flat-rate income tax, you must report your revenue in the dedicated boxes. This income enters the calculation of the reference tax income and the household's tax rate.
When do you declare micro-enterprise income?
The income declaration is made in spring, according to the tax administration's annual calendar, on impots.gouv.fr. It is a single declaration per year, distinct from the URSSAF revenue declarations made during the year.
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