This book is a historical novel, a piece of fiction. None of the characters has ever lived, the story, as it enrolls in the book, was made up in our minds. But the background of what happened in Berlin May to July 1945 is fact and based on our thorough research while writing.
It is fact that German women cleaned up the mess after the war, as most of their men were either POWs, injured or dead. In German, those brave women are called "Trümmerfrauen", which literally translates as "women of debris". The tough conditions under which they had to work are a fact the way we describe it. As well as hunger, broken water supplies, having no electricity or coal for cooking and a simple a lack of nearly everything you needed in daily life to provide a living for them and their children. And that far too many of the women in Berlin got raped by the Sovjet occupying forces is true, too. But they had hardly any right to complain, as they slowly discovered what crimes the Germans had committed during the preceding twelve years.
It is also a sad fact that, during World War II, gypsies – like Jews, communists, homosexuals, political opponents to the Nazis and many others – were imprisoned and finally killed in concentration camps, just like Camillo’s family.
Franz’s story is based on facts as well: The OSS (the American secret service during the war and shortly after, which than became the CIA) recruited former German SS officers to return undercover in Berlin to find Nazis of higher ranks who tried to flee. And the so-called "Rat line" mentioned in the book that provided a way to South America through Rome with the help of Vatican officials is a historical truth, too.
So all of the background is based on facts whereas the plot – the criminal investigation elements as well as the love story – is fictional.