Originally formulated in Chamberly, France by Joseph Dubonnet in 1846, Dubonnet wasn't introduced to Americans until after Prohibition. Usually Dubonnet is sipped on the rocks with a twist of lemon, but there are a few cocktails such as the Opera, Deshler and Zaza that call for its use.
Today, the Dubonnet available in America is made in Kentucky and is slightly different from the version made by the Dubonnet company in France. Dubonnet comes in both a red (rouge) and a white (blanc) version, with the red being the most common version for use in cocktails.