A lawyer representing a Jewish family trying to retrieve a long-lost Matisse painting looted by the Nazis said Tuesday a deal had been signed with the German government for its restitution.

London-based attorney Christopher Marinello, who works for the Rosenberg family, said that the order inked by German Culture Minister Monika Gruetters had now paved the way for the 1921 masterpiece "Seated Woman" to be handed back.

"I can confirm that an agreement has been signed for restitution of the Rosenberg Matisse," he told AFP in an email, following a report in German daily Frankfurter Allgemeine Zeitung to be published Wednesday.