Hackers have stolen the details of at least 1 million people in a massive cyberattack on the French tax office and land registry - here's how to check whether you are affected and what to do about it.
The General Direction of Public Finance (DGFiP) announced on Friday that there had been two separate hacks of its computer system in June and July.
In the first hack, in June, at least 678,000 people's details were taken from the French tax office system.
The second, in July, targeted the land registry - Serveur professionnel de données cadastrales (SPDC) - and saw 200,000 accounts compromised.
The thefts were claimed on a dark-web forum by Zerobytes, which has been associated with past hacks of French government computers. The cybercriminals said they had access to a VPN used by tax officials.
Prime minister Sébastien Lecornu will chair an emergency meeting on the hack on Monday.
Who is affected?
The tax hack potentially affects anyone who has an account on the French tax website gouv.fr - both individuals and businesses.
The tax account is used for the annual income tax declaration, which is compulsory for all French residents, as well as for property taxes for second home owners.
The business section is used by anyone registered as a business in France - including freelancers and contractors.
In total, around one fifth of accounts were hacked.
What details have been taken?
According to the French tax authorities, details taken include the person's full name plus details of their tax account, specifically the quotient familial (number of tax-payers per household), revenu fiscal de référence (total taxable income per household - the figure used to calculate whether people are entitled to government financial aid) and taux de prélèvement à la source (tax rate for people who have their income tax deducted as source, on a pay-as-you-earn basis).
For businesses, details taken include the SIREN (business number), business address and mandataire (named person responsible for tax matters, if it is not the business owner).
At this stage, it appears that login details and passwords were not hacked.
How do you know if you are affected?
The finance ministry says that anyone affected will be contacted "at the beginning of the week", so look out for an email from the tax office, or an alert that there is a new message in your tax account.
Those who are not contacted are not affected by this.
What should you do?
The tax authorities are expected to provide more details in the coming days about exactly what was taken and what precautions people should take.
In the meantime, it is advised to log in regularly to your tax account and check that no changes have been made to the account, other than those authorised by you.
This type of attack can also be used to create further phishing attacks - for example emails claiming to be from the tax office addressing you by name and providing details of your tax situation.
If you get an email that appears to be from the tax office, do not click any links - instead log in directly to your impots.gouv account and check the 'messagerie' section.
Check your bank account regularly for any suspicious or unusual transactions - for those who owe tax, genuine deductions by the French tax office will be taken on September 25th.
If you owe more than €300, the payments will be divided into four and taken on September 25th, October 26th, November 25th and December 28th.
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The tax office will never ask for bank details by email, phone or text message.
France is the European country most targeted by cyberattacks, with 43.4 million accounts compromised since the start of the year, according to data experts Surfshark.
