Exactly ten years after the genre-mixing, canine-driven Hungarian thriller “White God” landed the Prix Un Certain Regard at the Cannes Film Festival, this year’s ceremony culminated in the same prize going to a somewhat corresponding title: Chinese director Guan Hu’s “Black Dog,” a fusion of western, film noir and offbeat comedy with a highly lovable mutt at its center. The film, about a damaged loner returning to his desert hometown after a spell in prison and finding a kindred spirit in an equally world-weary greyhound, beat 17 other titles to take the top prize in the festival’s second-most prestigious competitive section. (The festival’s Official Competition awards will be handed out tomorrow night.)

Jury president Xavier Dolan, the actor-auteur behind such films as “Mommy” and “Laurence Anyways,” commended Guan’s film for “its breathtaking poetry, its imagination, its precision [and] its masterful direction.” He echoed the enthusiasm of Variety critic Jessica Kiang,...