As an adult, I viewed the name Gaston of Beauty and the Beast's villian, Gaston, as Gaston's last name. I only assume its his last name because 1)the triplet girls call him "Monsieur Gaston" which is basically saying "Mr. Gaston" in the opening song called "Belle" in the reprise that Belle sings によって herself the line "Madame Gaston, his little wife?" Most of the time saying "Madame (name" would be like saying Mrs. Gaston. And there's the fact Gaston is a first name but it could also be a last name as well. The name of Phantom of the Opera's author.