Errors in the tax return
In the event of an error in the tax return, there are several possibilities depending on the type of error:
If you have overpaid or under-declared VAT to be offset or refunded, you can request rectification of the self-assessment submitted within four years of the deadline for submitting it.
If you have underpaid or over-declared VAT to be offset or refunded, you must present a complementary self-assessment, ticking the "complementary self-assessment" box on form 303, indicating the number of the receipt of the previous self-assessment and filling in the "To be deducted (exclusively in the case of a complementary declaration)" box with the amount of the result of the previous self-assessment.
If you have requested compensation and want a refund, or vice versa, you can request rectification of the self-assessment filed if the deadline for filing the return has not yet ended.
If the error refers to an information box or the account number to which the refund is requested, or another error that does not affect the result of the settlement, you must submit a request for rectification of the self-assessment before four years have elapsed since the deadline for submitting it.