User Guide

 Whether or not taxes are included in each purchases.
 Whether or not taxes are displayed in the cart.
 Which customer address should the tax be based on.
 Whether or not an ecotax applies (read this WikiPedia page to learn
more about the ecotax).
If an ecotax does apply, a new field will appear in the product creation
page:
If you decide to take the ecotax in consideration after having added
products, you will have to edit them in order to set the tax properly for
each product.
The ecotax will also appear to the customer, on the product's page: