This is one of the most common tax mistakes, causing an average loss of 647 euros.

Many French people need to pay attention to this small line on their tax return. Filling it out incorrectly can lead to overpaying taxes.

The tax return, its multitude of boxes and the fear of making a mistake that goes with it... Despite the pre-filling of the main elements, "doing your taxes" - as they say - requires special attention. Not all the boxes that apply to you are automatically filled in by the administration, and it's best not to forget any to avoid inflating the bill.

This is particularly the case for a tax break that can affect up to 11.2 million French people and allows them to obtain a tax reduction. According to the Treasury, this is even one of the most common errors. And for good reason. "Many taxpayers don't double-check. We must be vigilant about this," warns Olivier Rull.

The head of Caravel, a platform that allows you to open and manage a retirement savings plan (PER), warns about the complexity of declaring a PER payment to the tax authorities. This is a point of particular concern because the advantage of investing money in this type of account is that it allows you to reduce your income tax. However, if this is not (or incorrectly) reported to the tax authorities, the reduction does not apply.

Everything is decided in the "Expenses" section, "Retirement savings, PERP and similar products (PER, PREFOM, COREM and CGOS)". If, between January ¹ and December 31, 2024, you made a payment into your PER, then an amount will appear above box 6NS. But be careful, this amount must absolutely be transcribed in box 6NS. Otherwise, the tax benefit will not be taken into account.

"Since an individual may have multiple PERs, it is their responsibility to complete box 6NS," explains Olivier Rull. Indeed, the amount displayed above corresponds to what the tax authorities are aware of. However, if amounts have been incorrectly transmitted or not transmitted at all, it is up to the taxpayer to correct them. This is why box 6NS must be completed by the taxpayer.

Furthermore, just below, box 6PS indicates the "deduction ceiling." Normally, an amount is pre-filled, but it's best, again, to check it. To do this, you need to look at your tax notice from last year. On the last page, the line "Ceiling for contributions paid in 2024" mentions an amount. If this is different from the amount indicated in box 6PS, then you need to make the change in the box, explains Olivier Rull.

On average, the PER saves those who make a payment during the year €647, according to figures from Caravel. This is the same amount of money paid to the tax authorities in the event of an incorrect declaration.