Seibert said the government is committed to finding just and fair solutions on looted art in private as well as public collections.
Paintings on the five-page list from the National Archive include Beckmann's "Lion Tamer," which Cornelius Gurlitt sold via Kunsthaus Lempertz in Cologne in 2011 after settling with the heirs of Alfred Flechtheim, a Jewish dealer persecuted by the Nazis and forced to flee Germany.
"Against the backdrop of the current revelations about the Gurlitt collection, the Flechtheim heirs are looking into whether there are any further works that used to be in Flechtheim's possession in the seized trove of paintings," the heirs said in a statement sent by email by the lawyer Markus Stoetzel.
The list obtained by Korte and Masurovsky also includes a Degas nude, several Beckmann oils, two Courbet paintings and an Otto Dix self-portrait — probably the same one investigators projected onto a screen at a news conference in Augsburg.
Other works in Gurlitt's collection in 1950 included paintings by Emil Nolde, Hans Thoma, Otto Mueller, George Grosz, Karl Schmidt-Rottluff, August Macke and the Italian painter Guardi.
"He liked Old Masters, German expressionists and French 19th-century paintings," Masurovsky said. "Gurlitt had a wide range."
Some works from the Munich stash were seized by the Nazis from German museums, while others may have been sold by Jewish owners under duress, said Meike Hoffmann, the investigating art expert. She declined to comment on estimates valuing the hoard at 1 billion euros ($1.35 billion).
Masurovsky said Gurlitt regularly acquired works at the Jeu de Paume in Paris, where the Nazis assembled art looted from French Jewish families during the occupation. Under agreements between the Allies, art looted from France was returned to the French government after World War II.