The IRS clarified that it will not challenge foreign tax credits relating to two kinds of French taxes—the Contribution Sociale Generalisee (CSG) and the Contribution au Remboursement de la Dette Sociate (CRDS)—due to a previous communication between the United States and France stating that these two taxes do not count as social taxes and therefore are not subject to the terms of the Agreement on Social Security, according to Accounting Today. 

The IRS’s change in policy means that individual taxpayers, who paid or accrued these taxes but did not claim them, can file amended returns to claim a foreign tax credit. Individuals will have 10 years to file a claim for refund on U.S. income taxes paid if they paid or accrued more creditable foreign taxes than what they previously claimed. Amended returns can be filed using Form 1040X to include accompanying Form 1116, going back to tax year 2009.

To claim refunds, individual taxpayers should write “French CSG/CRDS Taxes” in red at the top of Forms 1040X, and file them with the accompanying Forms 1116 in accordance with the instructions for these forms. However, U.S. employers cannot file for refunds claiming a foreign tax credit for CSG/CRDS withheld or otherwise paid on behalf of their employees. For more information, head to the IRS's site here, here or here.