There are very few accounts from Royal Air Force (RAF) personnel who served in France during the 'Phoney War' period of World War II which lasted from September 1939 to May 10, 1940. That is why this wartime journal by Arthur Hughes - who was a newly minted RAF pilot posted to France in October 1939...
Actually very useful reading. Testing language proficiency (whether you are an ESL or foreign language instructor) is difficult and misunderstood and most measurements of "fluency" are terribly inaccurate. Few institutions, in my experience, really bother to try to follow the principles in this book...