If “Owl and the Sparrow” were any slighter, it wouldn’t exist. Stephane Gauger’s debut feature is a charming little movie, nothing more, but he brings a tonic freshness to his simple, even simple-minded tale of a plucky orphan, Thuy (Pham Thi Han), playing cupid in Ho Chi Minh City, formerly Saigon. Mr. Gauger was fortunate to discover his unassuming lead; young Ms. Pham brings a humble, winning charisma to the role of a provincial girl who ditches her hardships to eke out a living selling postcards and flowers in the big city. But it’s the filmmaker’s infectious love for the metropolis — bustling and bright, whimsical and idealized — that gives “Owl and the Sparrow” its mellow vibrancy. — Jeannette Catsoulis