Operation Secret [1952 - USA] WWII drama

A few years after the end of WW2 a special French military commission is convened to summon witnesses who could shed light on an incident that took place during the war. The witnesses are all French except one who is American. The incident dates back to the French surrender to the Germans in 1940. One group of mostly French Foreign Legion soldiers refused to surrender to the Germans and being holed-up in a farm house continued to offer resistance to the Germans. Their officer, Capt. Armand Dupree, suggested surrender but his men called him a coward until they were ordered to surrender. After the Armistice some of them, prisoners of war in German POW camps, escaped and joined various resistance groups. The American, Peter Forrester, joins the US Army and is recruited by US Intelligence for his language skills and for the fact he had lived in Germany and France before the war. When he accepts a special mission behind enemy lines in occupied France, Operation Secret begins.