— The text
What exactly does article 1649 A of the Tax Code say?
The obligation to report accounts held abroad is in the second paragraph of article 1649 A (translated from the French text): individuals, associations and companies that do not have a commercial form, domiciled or established in France, must declare, at the same time as their income or results return, the references of the accounts opened, held, used or closed abroad.
Four verbs, and each counts: opened, held, used or closed. An account merely held, even without movement, must be reported; so must a third party's account over which you have a power of attorney that you also use; so must an account closed during the year. The report is made on form no. 3916-3916 bis, attached to the income tax return.
The third paragraph carries the most formidable presumption of the regime: sums, securities or values transferred abroad or from abroad through accounts not declared as required by the second paragraph constitute, unless proved otherwise, taxable income. Proof to the contrary consists in establishing that the sums have already been taxed, are exempt or fall outside the scope of tax (BOI-CF-CPF-30-20, § 240).
This text works together with the fine of article 1736, IV, 2 of the Tax Code (€1,500 per undeclared account, €10,000 where the account is located in a State that has not concluded with France an administrative-assistance convention giving access to banking information) and with the ten-year limitation of article L. 169 of the Book of Tax Procedures, set aside where the taxpayer proves that the total credit balances of the foreign accounts did not exceed €50,000 at any time during the year.
To fill in the form each year (accounts, life-insurance policies, crypto-assets), see reporting foreign bank accounts. To regularise omitted years, see regularising foreign accounts.