Combine the gin, lemon juice, tangerine juice, and honey in a cocktail shaker or any container with a fitted lid; cover and shake.

Put the sugar on a small plate and sprinkle the lemon and tangerine zests on top. Rub the rims of 6 champagne glasses with the lemon wedge, then gently roll in the zested sugar.

Divide the gin-citrus mixture among 6 glasses and top with champagne.