Local taxes: deadlines to anticipate between now and December 31, 2025

We will limit ourselves to the following 10 points:

1. Claims relating to local direct taxes and related taxes collected in 2024 must be submitted by December 31, 2025 at the latest (in the event of a tax adjustment or audit, please consult our dedicated page).
2. Property tax relief for vacant houses or unused industrial or commercial buildings that have reached the minimum required duration (three months) in 2024 must be requested by December 31, 2025, at the latest.
3. The request to cap the CET 2024 must be submitted by December 31, 2025, at the latest, using form no. 1327-CET (or no. 1327-S-CET for micro-enterprises).
4. If a business is established in 2025, a declaration form no. 1447-C must be submitted by December 31, 2025, at the latest, in order to report taxable items or benefit from any exemptions (form no. 1465 for certain territorial exemptions).
5. With regard to a change of operator that took place in 2025 (or took effect on January 1, 2025), the following provisions apply:^erJanuary 2026), a distinction must be made between the situation of the former operator and that of the new operator: the former operator must submit a declaration on plain paper indicating the items transferred, whether the transfer is total or partial (in the case of a partial transfer, it may be necessary to file an amended declaration for 2026). As for the new operator, they must complete the same reporting formalities as when creating a new establishment (see. supra, point 4).
6. Any new construction, any change in consistency or use, any change in the use of business premises, any change in the method of valuation of an industrial establishment, as well as any change in the category of residential premises or premises intended for the exercise of a salaried activity at home must be declared within 90 days of the event. For transactions carried out in September 2025, the declaration must therefore be made within 90 days of their final completion, failing which, where applicable, all or part of the temporary property tax exemptions may be lost (see. infra, point 7). Please note that, for initial planning permission applications submitted since January 1, 2016, the planning permission authority is the local authority where the project is located.^erAs of September 2022, the declaration relating to the development tax and, where applicable, the declaration relating to the preventive archaeology tax, is now included in the property tax declaration.
7. New constructions, reconstructions, and additions completed on January 1^erOctober 2025 must be declared by December 31, 2025 at the latest in order not to lose the benefit of property tax exemptions on built properties for 2026 and 2027. If the declaration is submitted after the deadline, the exemption applies for the period remaining after December 31 of the following year (the difficulties of interpretation related to this «catch-up» measure are detailed in our webinar on September 24, 2024).
8. For buildings eligible for preferential treatment for the first time in 2026 (energy-efficient housing, JEI, specific areas, etc.), the first application for temporary exemption must be submitted by December 31, 2025, at the latest.
9. Taxpayers wishing to switch to monthly payments from January 2026 must submit their request before December 31, 2025 (it should be noted that exercising this option between December 16 and December 31, 2025 will result in a double deduction in February, covering both January and February). Conversely, taxpayers wishing to opt out of the monthly payment plan as of February 2026 have until December 31, 2025, to cancel the option.
10. For companies subject to corporate income tax that closed their fiscal year on September 30, 2025, and although the theoretical deadline is December 31, 2025, the Administration is granting an additional period until January 15, 2026, to submit the Decloyer declaration.