Under Occupation by Alan Furst takes place in German-occupied Paris. The author lived in Paris for years, which undoubtedly contributed to the book’s strong sense of place. The initially reluctant spy is Paul Ricard. He writes detective novels for a living and makes some pretty funny comments about the craft of writing as the book moves along. Before he knows it he is deeply involved in the serious business of espionage. The plot concentrates on the captive Polish shipyard workers in Germany and their efforts to thwart the German war machine. It's a great page-turner with a lot of fascinating history.