Remi, Nobody's Girl

Remy, a cheerful and tender-hearted girl, lives with her mother in a French country town. One day her father returns to the town after a long period working away from home in a city. Her father tells Remy that she isn't their real daughter, and Remy is almost sold to an evil slave trader. It is Vitalis, a strolling entertainer, who helps Remy. Vitalis discovers her talent for singing and decides to take her in with his troupe.

(Source: Anime News Network)