Germany has returned an 18th Century painting that was looted from Poland's National Museum by the Nazis in 1939.
The piece by Venetian artist Francesco Guardi, entitled "Palace Stairs", was taken shortly after Germany invaded.
The small painting depicts noblemen talking at the grand stairs of Venice's Doge Palace.
Berlin hopes the move will revive talks over some 300,000 documents, including manuscripts by Mozart and Beethoven, that it wants to recover from Poland.
German Foreign Minister Frank-Walter Steinmeier handed the work over to his Polish counterpart Radoslaw Sikorski at a ceremony on Monday.
After World War Two, the painting went to the University of Heidelberg and then to the State Gallery of Baden-Wuerttemberg.
It was recognised as belonging to Poland in the late 1990s.
But political differences between Warsaw and Berlin over the broader issue of art lost during the war prevented a deal from being reached sooner.
"This painting has been on a long odyssey," Mr Steinmeier said.
"[It represents] the difficult history that connects our two countries."
Poland is still searching for thousands of artefacts looted from its museums and private collections during the war, although many items are believed to have been destroyed during the war.
Mr Steinmeier said he hoped the move would "be a signal to restart the stalled German-Polish dialogue on cultural artefacts".
Germany has long sought the return of some 300,000 books, drawings and manuscripts - known as the Berlinka collection - from Poland.
The collection includes handwritten musical scores by Mozart, Beethoven and Bach that the Nazis moved to Poland to keep them safe from bombing during the war.
Abandoned by retreating German troops in what is now Poland, many of the items are now held by the Jagiellonian University in Krakow.