Doux Champagne meaning "sweet" is sweet! With a high level of more than 50g dosage (sugar) added this is practically a dessert itself. Sweeter Champagne was very popular and is easier to make than dry but now as we haved moved towards drier styles, very sweet doux Champagnes are rare.
Doux Champagne shows affinities for both spice and richness so food pairing could be spicy Asian food where the heat is offset by the sugar in the wine. Some Doux Champagnes are promoting the mixing with ice and fruit as a Summer drink.
A higher dosage Champagne also allows for a changing palate when continuing to drink Champagne after a meal.