Currency exchange rates for foreign income

If you receive foreign income this must be converted to euros for your French declaration, which raises the question of what rate to use. 

The letter of the law states that you should use the rate on the day that you received the income into a bank account and the Banque de France’s rates are seen as the most authoritative. 

You can find daily rates, starting with the most recent dates and working back, by clicking the relevant ‘read’ button at this link: tinyurl.com/daily-ex.

That might work well if you received only a few one-off amounts in a foreign currency, however if, like many non-French nationals in France, you receive regular income in a foreign currency, such as sterling or dollars for a UK or US pension, the use of an average rate for the calendar year is tolerated.

Different methods are sometimes suggested for calculating this, but officials at the central tax authority DGFiP have told us that the following is acceptable: 

• Take the Banque de France month-end rates for December of the tax year in question (2025) and for December of the previous year (2024) and average them by adding them together and dividing by two.

This originally came from an Economy Ministry response to an MP who had asked about declaration of Swiss incomes of people living in Alsace tinyurl.com/swiss-alsace.

The information is also repeated at line 20 in this tax office bulletin page about taxable income: tinyurl.com/bofip-ex.

As it is ‘end of month’ figures that are required for the calculation, a search on the bank’s website for taux de change fin de mois is a quicker solution than looking for the individual days. Check here for December 2025 rates tinyurl.com/taux-fin-2025 and here for December 2024 rates tinyurl.com/taux-fin-2024.

Note that you do not want average rates for a given month, which are available, but end-of-month rates (parités fin de mois). 

By using this method, for the year 2025, we obtain the following euro to pound sterling rates: 

December 31, 2025: £0.8726

December 31, 2024: £0.8292 

Average: £0.8509

To find a sterling to euro rate, we then calculate as follows: 1 ÷ 0.8509 

The result, rounded to three decimal places is: £1 = €1.175 

The same calculation for US dollars gives: $1 = €0.903

You then multiply the amount of income in the foreign currency by the euro rate, to obtain the euro figure to declare.

It may help the tax office if you include a note explaining the rate you used and where it was obtained. On the paper forms there is usually an Informations box for extra information at the bottom of page 2 of the main form 2042. 

However, with most people now declaring online the question arises as to how to pass extra information on. 

You could use the mention expresse system, which is offered towards the end of the online declaration. 

Traditionally, this is to draw attention to something you are unsure of that you want the tax office to check but it is now the only way to provide a note as part of the online declaration. However, this is not obligatory. If necessary, you could just clarify to the tax office in the event of a question being asked.

If you use the annual average method described here and do optionally want to make a note about the method used to obtain the figure, you could use the wording such as the following: 

Revenus étrangers déclarés avec un taux d’échange moyen pour l’année 2025, calculé à partir d’une moyennne des taux de fin de mois de décembre 2024 et décembre 2025, suivant la méthode décrite dans le BOFiP-Impôts du 28/11/2016 (BOI-IRBASE-10-10-10-10-20161128). Les taux de la Banque de France pour la livre sterling étaient £0.8292 et £0.8726 

[Translation: Foreign income declared with an average exchange rate for the year 2025, calculated using an average of the month-end rates for December 2024 and December 2025, as described in the BOFiP-Impôts on 28/11/2016. The Banque de France rates for sterling were £0.8292 and £0.8726]