The ruling does not end France’s push for tighter digital safeguards, but it raises questions about how far the government can go without conflicting with constitutional protections.
The court found that the measure, which would have required platforms to prevent under-15s from creating accounts, raised serious legal concerns.
The decision challenges France’s attempt to impose age limits through national legislation while broader European rules govern online platforms.
Lawmakers and officials are expected to consider alternative measures, including stronger age-verification systems and greater parental controls.
The ruling comes amid growing concern across Europe about children’s exposure to harmful content, addictive design features and online harassment.
France has argued that existing platform safeguards are inadequate and that governments must take a more direct role in protecting young users. Social media companies, however, face increasing pressure to balance child safety, privacy and freedom of expression.