The URSSAF, a French organization responsible for collecting social security contributions, has the power to issue a "constraint," a legal document that allows it to recover unpaid contributions and late fees without needing a court order. This authority is based on article L244-9 of the social security code, and further explained in related articles. Unlike regular creditors, the URSSAF can begin forced recovery immediately, which can place debtors at a disadvantage because the organization acts as both the creditor and the authority issuing the claim. However, the constraint is not final; debtors have fifteen days from notification to challenge it. If they do not oppose it within that time, the constraint becomes as legally binding as a court decision, allowing the URSSAF to seize assets, income, or property. Before issuing a constraint, the URSSAF must send a formal notice, a legal requirement under article L244-2 of the social security code. This notice, sent by registered letter or other means with proof of delivery, gives the debtor one month to settle their debt. The notice must clearly state the reason for the claim, the amount owed, and the period to which it applies. If the notice is unclear or incomplete, the constraint may be canceled. In a 2026 case, the Metz judicial court canceled a constraint because the formal notice did not include the signatory’s name, making it impossible for the debtor to verify the authority behind the claim. Debtors must file an opposition within fifteen days of receiving the constraint, and this deadline is strictly enforced by the Court of Cassation. If the deadline falls on a weekend or holiday, it is extended to the next working day. The opposition must be filed with the social division of the judicial court in the debtor’s area and include a copy of the constraint. A simple objection is not enough; the debtor must provide specific reasons for challenging the claim. This process temporarily halts any asset seizures until the court decides on the validity of the claim. A constraint must include specific details, such as the reference number, the amount owed, the deadline for opposition, the address of the court, and the required forms for filing an opposition. If these details are missing, the constraint can be canceled. In a 2026 ruling, the Court of Cassation canceled a constraint because the address of the competent court was not included, preventing the debtor from knowing where to file an opposition. Additionally, the constraint can only be used to recover unpaid contributions and cannot be used to reclaim money that was mistakenly paid. The person who signs the constraint must be clearly identified, including their name, first name, and position, as required by the code of relations between the public and the administration. While in the past the Court of Cassation did not consider this detail essential if the organization was named, recent rulings have emphasized the importance of transparency. In a 2026 case, the Lille judicial court canceled a constraint because the signatory was not identified, highlighting the need for clear administrative procedures. Debtors can also challenge the actual amount of the debt if the URSSAF made a mistake in calculating contributions based on incorrect income data. Self-employed workers, in particular, may benefit from providing accurate income figures to reduce their debt. Other errors, such as incorrect payment credits or forgotten exemptions, can also be contested. The legal time limit for an uncontested constraint is three years from the date of notification or the last act of execution. However, in a 2025 ruling, the Court of Cassation canceled a 2021 seizure based on a 2018 constraint, stressing the strict enforcement of this rule. A 2026 reform extended the time limit for court decisions on opposition to ten years, which could increase the period debtors are exposed to if they contest and lose. Debtors who discover a constraint or seizure late still have options. They can challenge the completeness of the service act, the statute of limitations, or any irregularities in the legal title. They may also negotiate with the URSSAF for a payment plan or request a waiver of late fees. However, the recent reform means that debtors who contest and lose may face a longer period of legal exposure than those who do not contest. In summary, the URSSAF constraint is a powerful tool, but it is subject to strict procedural rules. Debtors must act quickly, within the fifteen-day deadline, to challenge the validity of the constraint. Proper documentation, including the formal notice, service act, and constraint itself, is essential. While the process can be complex, it offers debtors the chance to contest the claim, potentially leading to its cancellation or a reduction in the amount owed.