Lots of time people got confused between Champagne and Sparkling wine. Many people uses the word Champagne when they open any sparkling wine.
You guys probably already know this thing that Champagne comes solely from Champagne region of France. Its made from any or all three grapes: Pinot Noir, Pinot Meunier and Chardony. Though process of making all sparkling are almost same.
So there is only one difference that the sparkling produced in Champagne are Champagne and others are not.