A two-year inquiry found that the paintings belonged to the heirs of Jacob and Rosa Oppenheimer, who ran a gallery in Berlin in the 1930s, the Los Angeles Times reported Tuesday.
Two of the paintings are to be returned to the family Friday in Sacramento. The heirs allowed California to retain ownership of one of the Venetian paintings, which date from 1500 to 1590.
Wealthy US publisher William Hearst had acquired the paintings at a 1935 auction, unaware of their origins, for display at his palatial estate in San Simeon on the Californian coast.
The multimillionaire collected antiques and artwork from across Europe for his famous home, which today is a tourist attraction. Ownership of the estate was transferred to the California Department of Parks and Recreation in 1972.