The techniques of sparkling winemaking did not originate with the Benedictine monk Dom Pérignon, nor was the first purposely sparkling wine produced in the region of Champagne. Regardless, through centuries of refinement Champagne has become the world’s leading sparkling wine and the vinous embodiment of luxury and celebration.
You've named the guy who determined the precise amount of sugar to be used in second fermentation as André François, but both the OCW and de CIVC web site name him Jean-Baptiste Françoise