The American descendants of the Wertheim family, which once ran a grand department store at the disputed site, known as the Lenne Triangle, next to central Berlin's Potsdamer Platz, claim the family lost their business empire under Adolf Hitler's anti-Semitic "Aryanization" laws.

After World War II, the occupying authorities awarded the real estate to retailer Hertie. The property lay in no-man's land between East and West Berlin during the Cold War before being purchased by KarstadtQuelle in 1994. The company then sold the property to Swiss tycoon Otto Beisheim in 2000 for 145 million euros ($183.5 million).

Barbara Principe, who originally went by the surname Wertheim, was just a young girl when her family was forced into exile in the 1930s and the Nazis confiscated their business and property. She and two of her grandsons have been lobbying KarstadtQuelle in Germany to pay reparations for the past year.