Choosing the right Champagne means already making the difference between brut nature, extra-brut, brut, extra-sec, sec, demi-sec, and sweet. The difference is made between the residual sugars which are more or less important according to the mention on the bottle:
Brut Nature contains the fewest residual sugars in the bottle (less than 3g / L), Extra-Brut is the name of champagne with a residual sugar level between 3 and 6g / L. The most common remains the Brut with more sugar than the extra-brut. The Extra-Sec, the sec and the demi-sec, contrary to their name, are much sweeter Champagnes than the brut, extra-brut and brut natures they can contain up to 15 g / L of sugar.
Avoid on the label the mention Bouteille MA (auxiliary mark), also pay attention to the selling price below 16 euros it will be difficult for you to find a quality champagne because a bottle contains on average 9 euros of raw material.