What triggers a tax inspection in France? Warning signs explained

The French tax authorities recovered some €11.4 billion in back tax and penalties after inspections last year - a figure that has been rising due to increasingly sophisticated tools. 

With errors and frauds now more likely to be spotted, it is all the more important to take care over your declaration and avoid triggering checks. 

The authorities use several methods to check for fraudulent activity, including AI as they attempt to crack down on the issue, and frequently take part in international information exchanges with other agencies to identify discrepancies.

However, they can also verify annual declarations and other tax information provided in France for irregular activity.

They can target declarations based on irregularities, inconsistencies, or comb through to ensure that there is no incorrect use of elements such as tax credits.

Below, we look at the different behaviours and inconsistencies which might trigger checks and potential penalties from the tax authorities, as well as the different types of audits that take place.

It is worth noting, however, that while deliberate fraud is subject to tough penalities in France, there is a principle of droit à l'erreur (the right to make a mistake) meaning that genuine mistakes, especially where it is a 'first offence' are often treated leniently.

Remember, also, that it is easy to correct a declaration you have made up until your deadline, and even after that an online corrections service opens in the summer via your impots.gouv.fr account. 

Dramatic changes in income

If your income appears to go up and down in an irregular and unexplained manner, it may attract the attention of the tax authorities, even if the changes are due to a legitimate reason.

You will often be asked to clarify why your income has fluctuated, so make sure that you explain truthfully and clearly.

This applies both to individual declarants and businesses.

Tax authorities have a growing number of ways in which to identify people committing fraud and they are now authorised to check social media to see if a person's lifestyle matches with their tax declaration.

Therefore, if someone posts references to their wealth online but does not declare a high income, it may trigger a tax inspection.

Online platforms such as Airbnb will also share details of earnings on them.

A significant proportion of inspections come after officials notice an incongruity between a person’s tax declaration and their visible lifestyle (train de vie).

False expenses claims

This issue particularly affects self-employed workers on the réel tax regimes who can declare professional expenses linked to their business activities to reduce the amount of tax they have to pay.

Exaggerating the amount paid out for these expenses can trigger a tax inspection, so you should take care to keep a detailed record of your accounts.

Consistently late or wrong tax returns

If you repeatedly return your income tax declaration after the deadline, you may attract the attention of the authorities.

It is therefore helpful to set alerts for yourself well ahead of the declaration deadline so that you can get started while you still have plenty of time.

Deadlines for the 2026 income tax declaration (based on earnings from 2025) can be found in our article here.

As mentioned, in France, it is understood that genuine mistakes and omissions can occur, but it is best to proactively look to update authorities with the correct data if you become aware that you made a mistake. 

However, consistently making errors (especially similar ones) across several years or elements of a declaration, or a major omission may lead to an investigation, particularly if you fail to inform the authorities of the mistake.

Investigations are also more likely if you provide contradictory information to various government authorities (tax services, CAF, Urssaf, etc).

A main home which is not really your main home

If you put your main residence on sale but the process drags on for too long and you have stopped living there for too long - usually a year - the tax authorities can refuse to class it as your principal residence, thus making it eligible for capital gains tax (CGT).

This might happen, for example, if someone moves away quickly for work and leaves the property before they have a chance to put it on the market.

In addition, if you work from home and have declared to the tax office that part of it is being used for professional purposes, you should also declare this when the property is sold otherwise the tax office could query why it is being sold solely as a residence (with exemption from CGT).

Tax authorities are also targeting those who falsely declare second homes as main properties in an attempt to avoid the taxe d'habitation second-home tax.

Under-declaring wealth for IFI tax

If you are an IFI wealth tax payer (the impôt sur la fortune immobilière), take care to give a ‘reasonable’ market valuation of your holdings.

Increasingly, tax offices are making checks, especially when properties are passed on or sold, to see if they have been valued realistically.

If necessary, it might be better to admit to a ‘mistake’ in the past, and pay extra tax than deal with further penalties.

Foreign and online bank accounts must be declared

As a reminder, all foreign (non-French) bank accounts should be declared on your tax return.

Online banks and neobanks are becoming increasingly popular, especially for people who often travel to different countries.

However, some of these institutions are not based in France, so in this case you will need to declare these as 'foreign' accounts.

If you do not make this declaration, you face a fine of €1,500 per non-declared account.

Bear in mind that the cross-border sharing of information is common now. 

If you opened accounts in previous years, it is advisable to own up to them, as tax offices are likely to be more tolerant of genuine mistakes admitted to them than where they discover accounts themselves.

French accounts, meanwhile, should be known to officials.

Take care over nue-propriété and usufruct within families

Parents can be tempted to make an arrangement to reduce liability to inheritance tax by giving the nue-propriété (residual ownership) of their home to their children while they maintain the usufruit (lifetime use).

When they die, their children will become the owners of the property.

The children should not live in the home for extended periods unless a full rent is paid, as otherwise it can be seen as a disguised full gift of the home (donation déguisée).

Renting out a property owned through a Société civile immobilière

If you part-own a property as part of a Société civile immobilière (SCI) – which enables the management of a property which is owned jointly and can reduce tax liability – but decide to use it for commercial purposes such long-term rentals, this should be planned carefully and it is advisable to take advice as to tax consequences. 

It may be necessary to change its tax regime so that incomes from it will be subject to impôt sur les sociétés rather than ordinary income tax. 

Failing to undertake the correct formalities can lead to penalties. 

A pension alimentaire is only for essential needs

If you financially support family members in need and declare this in your tax declaration, you will be eligible for tax breaks.

However, the sums paid should only go under the pension alimentaire heading – as opposed to being a potentially taxable gift – if they are for ‘essential needs’.

For example, if you gave a significant amount of money to an independent child earning at least the minimum wage, you would likely be seen to be breaking pension alimentaire rules.

Loans between family members

Financial dealings between family members are also sometimes a red flag for authorities. For example, take care in the case of large loans, which could be seen as a disguised gift.

All large gifts, outside normal presents, can be taxable under droits de donation. 

If you lend €5,000 or more in a given year, including in several amounts or to different people, you are expected to declare this loan to the tax office, if the recipient has not done so.

Otherwise the loan may be considered as a gift.

If you receive loans of €5,000 or more in a given year, you should also declare.

A famous case last year saw a family hit with a €1.3 million tax bill over a family loan made more than 30 years ago that was never repaid.

Abuse of the Pinel rental tax reduction system

People who have invested in the Pinel mechanism to obtain a tax reduction on a property bought for rental should respect certain conditions relating to limits on the amount of rent they can charge.

You should pay attention to the specific rules for your area, and any changes that might be made to them, as failing to do so could mean that you lose your tax reduction and are fined.

What happens during an investigation?

There are two main kinds of investigation, the more common contrôle sur pièces (a smaller check based on documents) and a thorough process called an examen contradictoire de la situation fiscale personnelle (ESFP).

During the former, declarants are often not informed that the check is taking place, and it usually consists of authorities checking information and documents or cross-referencing data. 

However, auditors may ask for additional information or paperwork, such as proof of a demanded tax reduction. 

An ESFP is much less common, and involves in-person meetings between the individual and tax officials, with investigations lasting for up to two years.

More information about audits can be found in our article here.

The Connexion has published a guide to completeing the 2026 income tax declaration (for 2025 income), available here.