An example of good cheese that you can get from Carrefour: one of my favorite cheeses is Soumaintrain, a cheese from northern Burgundy that is extremely difficult to obtain outside of Burgundy because of its low production. Under the Reflets de France label, my local Carrefour offers 250g wheels of Soumaintrain for just a bit more than 5€. Those who read the fine print will see that the cheese is produced and matured by the respected Gaugry firm in Brochon (the village immediately north of Gevrey-Chambertin). Gaugry produces two types of Soumaintrain, one pasteurized and one from raw milk – this is the pasteurized version, but still, it is quite good for what it is.
More on reading the fine print: the Reflets de France Moutarde de Bourgogne is from Fallot, one of the finest (if not the finest) mustard producers in France.