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The Kir royal is a French cocktail, a variation on the Kir. It consists of crème de cassis topped with champagne, rather than the white wine used in traditional Kir. This apéritif is typically served in a flute glass.
KIR from IBA, "KIR Before Dinner Cocktail 9 cl Dry White Wine 1 cl Créme de Cassis Pour Créme de Cassis into glass, top up with white wine. For Kir Royal: Use champagne instead of white wine."