The government-backed German Lost Art Foundation said Monday that 502 works have been evaluated, including pieces by Paul Cezanne, Eugene Delacroix and Albrecht Duerer.
The foundation is tasked with researching the origin of art hoarded by Gurlitt, who died in 2014. He had kept more than 1,200 works in his Munich apartment and 250 more in Salzburg, Austria.
Gurlitt's father, Hildebrand, was an art dealer who traded in works confiscated by the Nazis.
Hundreds of photos of Hildebrand Gurlitt's art collection were published online earlier this year by Germany's Federal Archives as part of the effort to find the rightful owners.