Gin, lemon, simple syrup, and Champagne — named after the French 75mm gun because it hits with equal force.
The French 75 was named after the French 75mm field gun used in World War I — the fastest artillery piece of the war, capable of firing 15 rounds per minute. The cocktail first appeared by this name in the 1927 'Here's How' cocktail guide, and was popularised at Harry's New York Bar in Paris.
The New Orleans version uses Cognac instead of gin — Arnaud's French 75 Bar has been serving the brandy version since 1918 and insists it's the original. The gin version became standard in most bars partly because gin was more accessible internationally. Both are excellent; the Cognac version is richer and more complex.
Replace gin with Cognac VSOP. The New Orleans way — richer, warmer, more sophisticated. Particularly good for special occasions.
Replace gin with vodka and add a small dash of Cointreau. Lighter, more approachable, and popular at brunch.
Replace simple syrup with elderflower liqueur (St-Germain). The floral notes elevate the botanical gin character beautifully.