What would you buy through French system called appellation d'origine controle or an Italian system called denominazione di origine controllata e guarantita?

Wine

This is a system for assessing the origin and other requirements for goods. It is common for some cheeses and wines in France to go through this assessing system. A cheese maker can be asked to prove that the milk he collects comes from a designated area and that he uses the correct equipment and processes to make his cheeses. A wine grower will be asked to use grapes coming from designated areas and its production will have to undergo testing / tasting by a certifying panel.

Wine, cheese, and a number of agricultural products have to be certified under this system. Certification enables the maker to claim he is up to the standards and makes his sales easier, especially when the appellation name is prestigious (Champagne, Sancerre, Crottin de Chavignol)