Option 1: DST upheld as constitutional
If the Court finds the DST fully compliant with the French Constitution, further challenges to the DST — on any constitutional grounds — would generally be precluded.

Option 2: DST found unconstitutional
Should the DST be ruled unconstitutional, DST liabilities would, in principle, cease to apply. Taxpayers could seek reimbursement for DST already paid, subject to any applicable time limits. However, based on past practice, the French Constitutional Court may limit the effects of its decision to future fiscal years and ongoing litigation concerning past years. Taxpayers wishing to preserve their rights should therefore consider initiating litigation before the French Constitutional Court’s decision, which is expected before 17 September 2025 (the exact date has not yet been announced).

Option 3: Partial unconstitutionality
The French Constitutional Court may find only certain DST provisions unconstitutional - for example, specific exclusions that may violate the principle of equality before the law, which would extend the scope of the French DST (however, in such a case, the Constitutional Court would likely restrict the effect of its decision to future fiscal years).