Pierre Le Guennec and his wife were convicted last year of possessing stolen goods for hiding the works from Picasso's heirs.
At his original trial Le Guennec, who is in his late seventies, claimed that Picasso had presented him with the artworks towards the end of his life to reward him for his loyal service.
But he later changed his account, telling the appeal court that the works were part of a huge trove of art that Picasso's widow asked him to conceal after the artist's death in 1973.
He claimed that Jacqueline Picasso later retrieved most of the works but left him a bag containing 180 single pieces and a notebook containing 91 drawings as a gift.
The collection, whose value has not been assessed, includes drawings of women and horses, nine rare Cubist collages from the time Picasso was working with fellow French artist Georges Braque and a work from his "blue period".
Other more intimate works include portraits of Picasso's mistress Fernande, drawings of his first wife Olga and a drawing of a horse for his children.
French authorities seized them after Le Guennec presented them to Picasso's son Claude Ruiz-Picasso in 2010 to try get them authenticated.
Ruiz-Picasso, who represents the artist's six heirs, subsequently pressed charges.