According to Christian Petzold, this movie is the last chapter of his trilogy called "Love in Times of Oppressive Systems". The trilogy also includes Barbara (2012) and Phoenix (2014).
The film is a World War II allegory set in modern times. It is based on a novel set during WW2 in Nazi-occupied France. While the plot remains unchanged the era the movie is set in is changed to be the 21st century. To compensate for this, some elements of the plot are left vague such as who exactly is the occupying force.
According to Christian Petzold, in some ways, all of the screenplays that he and his late collaborator Harun Farocki developed together were more or less based on Transit by Anna Seghers.