Fantina

Fantina (Japanese: メリッサ Melissa) is the Gym Leader of Hearthome City's Gym, known officially as the Hearthome Gym. She hands out the Relic Badge to Trainers who defeat her. She specializes in Ghost-type Pokémon.
She is apparently not from the country the games are set in, and often peppers her speech with phrases of French (English in the Japanese and French versions).