The Paris Architect by Charles Belfoure
Like most gentiles in Nazi-occupied Paris, architect Lucien Bernard has little empathy for the Jews. So when a wealthy industrialist offers him a large sum of money to devise secret hiding places for Jews, Lucien struggles with the choice of risking his life for a cause he doesn’t really believe in. Ultimately he can’t resist the challenge and begins designing expertly concealed hiding spaces—behind a painting, within a column, or inside a drainpipe—detecting possibilities invisible to the average eye. But when one of his clever hiding spaces fails horribly and the immense suffering of Jews becomes incredibly personal, he can no longer deny reality.
Written by an expert whose knowledge imbues every page, this story becomes more gripping with every life the architect tries to save.