Since January 1, 2023, Luxembourg employers who allow their French frontier workers (who remain under the Luxembourg social security regime) to exceed the 34-day tax tolerance threshold, are required to declare the portion of their salary that is taxable in France1 to the French tax authorities. For the year 2025, this declaration, known as “PASRAU,” must be made no later than February 10, 2026, after the closing of the Luxembourg payroll.