Erich Mielke, the head of the East German secret police, was a great fan of Orwell's novel 1984, and desperately wanted his office to be in Room 101 (the location of the torture chamber in the novel). His office was on the second floor. So he renamed the first floor the mezzanine.
"I'd long been fascinated by George Orwell's work, but I resisted reading 1984 until I finished the manuscript for Stasiland. After that, I devoured it, and I couldn't believe Orwell's prescience. When I went into Mielke's office, I saw it had the number 101, which in 1984 is the number of the torture chamber. 1984 was banned in the G.D.R. but of course, Mielke and Honecker had access to banned material. The guide told me that Mielke wanted this number so much that even though his office was on the 2nd floor, he had the entire first floor renamed the Mezzanine so that he could call his room 101."
–Anna Funder, author of Stasiland