The cache includes lithographs, portraits, a watercolour and sketches created between 1900 and 1932.
Pierre and Danielle Le Guennec said they were given the art, worth €80 million (£59m) by Picasso’s second wife.
The Picasso estate said their account is “ridiculous” and is suing them for illegal possession of the works.
Picasso’s son Claude has insisted his father would “never” have given such a large quantity of works to anyone. He said: “That doesn’t stand up. These works were part of his life.”