The document was approved by Russia's lower and upper houses of parliament in March. Under the agreement between the two countries, Germany will cover the costs for transportation, security and authentication of the stained glass windows.
In 2002, Russia returned 111 stained glass windows to St. Mary's Church, Marienkirche, in Frankfurt-upon-Oder. They had earlier been stored in the Hermitage museum in St. Petersburg.
Authorities later discovered that Moscow's Pushkin Museum of Fine Arts had a further six panes in their stores. After the windows are returned to Germany, they will be reinstated in the church, which has recently been restored.
Russia and Germany have pledged to return valuable works of art captured from each other during World War II. The process, however, has proceeded slowly, as many in Russia consider the artifacts compensation for the country's wartime losses, and both sides are anxious not to lose out in the exchanges.
During WWII, the Nazis looted works of art throughout Europe and the occupied parts of the then Soviet Union, secreting many of them into Nazi leaders' private collections. After the war, Soviet security bodies moved to return as many of them as possible, also confiscating other cultural objects as military trophies.
The actual volume of cultural objects looted by Germany and Russia is unknown, as many of them were destroyed or stolen by individual soldiers.
One of the most famous objects lost in the war was the legendary Amber Room, made in Prussia in the early 18th century, and believed to have been looted by Nazi troops in 1945.
In February, media reported that the Amber Room may have been discovered by treasure hunters at an underground site near Germany's border with the Czech Republic. The excavation recently ground to a halt, however, after a disagreement between the people leading the dig.
