MONTREAL - A recent U.S. court ruling is giving a serious boost to the efforts of those trying recapture lost Jewish-owned heirlooms that were forcibly sold during the Nazi era in Germany.

A U.S. District Court judge ordered a German baroness to hand over the painting as it rightfully belongs to the estate of a Jewish-Canadian art dealer who was forced to auction it off before he fled Nazi Germany in the late 1930s.

Judge Mary Lisi ruled the painting in question rightfully belongs to the estate of Max Stern, a Canadian art dealer who lived in Montreal and passed away in 1987.

The decision is believed to be the first in U.S. history to equate the forced sale of Jewish-owned art in Nazi Germany to theft.

"A verdict on a painting stolen during the Nazi period that identifies a forced sale being equivalent to a theft is incredibly important, not only for the Max Stern project, but for all individuals who are in the process of understanding what they lost to the Nazis in the war,'' said Clarence Epstein, director of the Max Stern Art Restitution Project at Concordia University.

"It's not only for the estate but for all for future actions regarding the issue of looted art and forced sales.''

Stern passed away in 1987 and left his estate to McGill and Concordia universities in Montreal and Hebrew University in Jerusalem, who have continued to search for the missing 400 paintings.

The judge ordered Maria-Luise Bissonnette last Thursday to turnover the painting "Girl from the Sabiner Mountains'' to Stern's estate.

"It is clear that Dr. Stern's relinquishment of his property was anything but voluntary,'' Lisi wrote in her decision.

Bissonnette, living in Providence, R.I., has not said whether she will appeal the decision and could not be reached on Friday. She has insisted that her family did nothing wrong.

Outside experts have not authenticated the painting but both sides claim it is a work of Franz-Xaver Winterhalter, a 19th century artist noted for his portraits of European nobility. An appraiser for Bissonnette estimated the painting, stored in a German warehouse, is worth as much as $94,000.

Stern's collection is believed to be worth more than US$10 million.

Bissonnette's stepfather, a Nazi party member named Karl Wilharm, acquired the painting during a forced sale at Lempertz Auction House in Cologne, Germany, in 1937.

Stern's estate was negotiating to have the painting returned until 2005, when the baroness quietly shipped the painting to Germany.

"With this decision we have a precedent that helps bolster our arguments when we submit to claim the hundreds of other works we're pursuing,'' Epstein said.

The U.S. decision is also causing a stir in Germany. Art experts in that country understand the ruling could apply to many other pieces of lost German-Jewish art, said Willi Korte, a historian and former war crimes investigator who is now investigating the Stern claims.

"All the other cases that went to court and reach the level of decision ... were paintings that were out-right taken, stolen, seized,'' said Korte.

"Our big challenge here was to introduce a lost painting that was lost due to a forced sale.''

The majority of the Stern artwork is believed to be in Germany, but the United States is one of the world's major art markets. Only about 40 of the 400 missing Stern paintings have been identified. Paintings re-appear on the art market periodically all over the world.

"I can't take this decision and apply it in Europe or in Germany, where most of these paintings appear,'' Korte said.

"But everyone realizes the international art market is an international one and you can't just ignore the U.S. market.''