Yes, since 1 October 2026: Article D. 541-244 of the Environmental Code allows anyone to calculate and publish a garment's environmental cost without the brand's agreement. Some data are public (composition on the label, garment-making country), but the third party must also provide the mass and weaving and finishing countries, then submit its calculation on the portal before publishing. Before that date, the brand's agreement was required, or it had to have published its cost on the portal already. The only way to retain control is to publish your detailed data first.
Read the source article: Environmental labelling: what are the risks of not publishing?