1. Add an ecotax classification via the menu **Accounting > Configuration > Taxes > Ecotax Classification**.

   - The ecotax classification can be either a fixed ecotax or a weight-based ecotax.
   - Ecotax classification information can be used for legal declarations.
   - For the fixed ecotax, the ecotax amount is used as a default value, which can be overridden on the product.
   - For the weight-based ecotax, define one ecotax by a coefficient applied to the weight (depending on the product's materials).

2. Assign one or more ecotax classifications to a product.

   - The ecotax amount can also be manually overridden on the product.

3. Create an invoice with this product