Is the movie dunkirk more fictional or factual to the real event? provide examples

It starts in May 10, 1940, with a surprise German blitzkrieg bombarding Holland and the French-Belgian border with air raids, parachute drops and ground attacks. The move came as a surprise to the Allied forces, who had thought any German attack would come at the Maginot Line, a fortification along the French-German border. And it was apparently a surprise to some Germans too, according to Robert Tombs, a historian at the University of Cambridge and a co-editor of Britain and France in Two World Wars: Truth, Myth and Memory, since it was a risky last-minute decision that Nazi dictator Adolf Hitler almost didn’t sign off on.

i think the answer is true

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