I have an idea for a novel, but I need to understand a lot more about french society leading up to and during WWII. I have a number of topics I'd like a better historical perspective on.
Civilian life from before WWI and continuing on to the occupation.
The French Resistance. Tactics and general culture, as well as how they were viewed by those not actively resisting.
Covert operations in France.
Stage magic, particularly in France during this period.
Any collection of folk tales that would have been commonly told to children in this period that are uniquely french.
the operations of the occupying government, it's policies, and it's leadership.
As a quick recommendation, I am a massive fan of Julian Jackson's work on France in the 1930s. That is, The Popular Front in France, The Fall of France and France: The Dark Years. (The Politics of the Depression in France is also worth a read but is slightly denser and more economic in nature.)
Collectively these works cover the political and social struggles from 1932-1945. All very readable and excellent at laying out the increasingly bitter faultlines that came to mark the country's pre-war years. I would certainly start with those if you're looking to understand the pre-war environment, how France was defeated and the Vichy regime, respectively.