Close to 1400 paintings were seized by German authorities at an apartment belonging to the son of noted German art dealer Hildebrand Gurlitt.
Although the works were removed in March 2012, the news of the find was only announced this month, after an exposé by Focus Magazine.
It is thought that many of the works had been looted by the WWII Nazi regime, as Gurlitt Senior had been a collector of what the Nazis deemed as 'Degenerate Art'.
German prosecutors had not previously released details earlier for legal reasons.
However, owing to international pressure, 25 paintings were confirmed by the Public Prosecutor's Office Augsburg and they have since been listed on the Lostart web site.
Art experts have noted that the provenance of each picture is extremely complicated but Justyna Lewanska has already said that papers exist confirming that Max Liebermann's painting Riders on a Beach belongs in a Polish collection.