A stranger called Gennady Zyuganov's office in the headquarters of parliament's lower house in the morning, saying he would like to give the picture to the Communist leader, party spokesmen said.
"Once the canvas was brought in, we began searching for information about the painting, and eventually came across an official statement by the Hermitage administration saying that an unidentified person had cut Jean Leon Gerome's 'Piscine du Harem' ['Harem Pool'] out of its frame on March 22, 2001," Zyuganov said.
The 1878 picture, measuring 73.2 x 62 cm, was bought into Russia by Emperor Alexander III, and its value is estimated at $1 million.
Zyuganov said he is now waiting for a group of experts from the Culture Ministry to come and test the picture for authenticity.
More than 200 artworks were discovered missing from the Hermitage, one of the world's richest and finest art collections, during an inspection in August. Inspectors said the missing items had presumably been stolen over a period of several years and that members of the staff may have been involved.
The mass theft uncovered at the Hermitage raised doubts over the reliability of Russian museums' security systems, prompting federal authorities to order checks nationwide.
