The Kir royal is a French cocktail, a variation on the Kir. It consists of

crème de cassis Crème de cassis () (also known as Cassis liqueur) is a sweet, dark red liqueur made from blackcurrants. Several cocktails are made with crème de cassis, including the popular wine cocktail, kir. It may also be served as an after-dinner liq ...

topped with

champagne Champagne (, ) is a sparkling wine originated and produced in the Champagne wine region of France under the rules of the appellation, that demand specific vineyard practices, sourcing of grapes exclusively from designated places within it, ...

, rather than the white wine used in traditional Kir.The Classic Champagne Cocktail – Kir Royale Fits Everyone
"Glass: Flute (champagne), Wine glass … fill it with your champagne or sparkling wine"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." This apéritif is typically served in a flute glass.

References

Cocktails with Champagne Cocktails with liqueur {{cocktail-stub