BERLIN — Cornelius Gurlitt, the octogenarian hoarder of art plundered by the Nazis, will return paintings in the trove his family kept secret for decades to their original Jewish owners or those owners’ descendants, starting with a well-known Matisse, his lawyers said.

Gurlitt’s lawyers are in talks to return “Seated Woman/Woman Sitting in Armchair” to the descendants of Paul Rosenberg, a French art dealer whose family recognized the work when it was made public last year.

“The agreement is not yet signed, but it will certainly happen,” said Gurlitt’s spokesman, Stephan Holzinger.

Christoph Edel, a lawyer appointed by a Munich court to handle Gurlitt’s health, financial and legal affairs, told the German broadcaster ARD that more deals were coming. Gurlitt, 81, who has heart problems, had surgery recently and has been slow to recover, leading the court to appoint a legal guardian.

“Mr. Gurlitt has given us free rein to return those pictures that belonged to Jews to their previous owners or their descendants,” Edel said last week.

The news that Gurlitt had hoarded hundreds of prints, drawings and paintings collected by his father, an art dealer who worked for the Nazis as they seized Europe’s treasures during World War II, set off international outrage when their existence was made public in November. After pressure from Jewish groups, the United States and Israel, a team of international experts was formed to evaluate the 1,280 works in the collection, known as the Munich Art Trove.

Those works are in the possession of the German authorities who seized them from Gurlitt’s apartment in Munich, but the full extent of the collection is unknown. Experts sent last month to Gurlitt’s second home in Salzburg, Austria, found more pieces.

Among 39 oil and watercolor paintings are works by some of the biggest names in modern art: Claude Monet, Édouard Manet, Pierre-Auguste Renoir, Paul Cézanne, Emil Nolde and Max Liebermann.