You calculate it on Ecobalyse, the free public tool developed by the Ministry of Ecological Transition and ADEME, by entering the product's characteristics: type, mass, material composition and the countries of weaving or knitting, dyeing and finishing, and garment making. The country of spinning is optional. For the optional parameters, each missing item of data is replaced by a conservative default value, which can raise the score. You therefore need to collect supplier data, including from tier 2 and tier 3 suppliers. Start with a pilot product and allow 8 to 10 weeks to stabilise the method before extending it to the catalogue.
Read the source article: French textile eco-score: is it mandatory for your brand?