Previously unknown artworks by masters including Marc Chagall, Otto Dix, Max Liebermann and Henri Matisse are among those found inside a flat in Munich.
Prosecutors said the issue of ownership was still to be clarified. The total value has been estimated at about €1billion (£846 million).
Other artists whose works were found include Pablo Picasso and Henri de Toulouse-Lautrec, as well as Canaletto and Gustave Courbet.
More top news
A young man dramatically rescued by the Turkish coastguard from a sinking boat has spoken of his ordeal.
Temperatures tumbling in the clear skies
Police have launched an investigation and are trying to establish the age of the baby and how long the body has been in the drain.