Do we know if George S. Patton said that even though George C. Scott quoted Frederick the Great in the movie?
If Patton did, what does the quote actually mean in the situation?
The context of the speeches to the Third Army is the preparation prior to Normandy's landings. For American soldiers involved in this operation, this was the first big action of the war. However US Army had already fought hard battles in Africa and hard landings in Sicilia and Italy.
So Patton needed to motivate soldiers that had had a conventionnal training to be as involved as their counterparts in the Mediterranean Sea, and from a larger point of view as Marines in the Pacific or airmen over German's plants. The issue was not the strategy nor the tactics, it was about giving inexperienced soldiers the willingness to fight in dangerous operations such as a landing.
In this context, the quote "l'audace, toujours l'audace" is perfectly understandable. Patton also gives this sort of example:
One of the bravest men I saw in the African campaign was on a telegraph pole in the midst of furious fire while we were moving toward Tunis. I stopped and asked him what the hell he was doing up there. He answered, 'Fixing the wire, sir."Isn't it a little unhealthy up there right now?' I asked. 'Yes sir, but this goddamn wire has got to be fixed.' I asked, 'Don't those planes strafing the road bother you?' And he answered, 'No sir, but you sure as hell do.' Now, there was a real soldier. A real man. A man who devoted all he had to his duty, no matter how great the odds, no matter how seemingly insignificant his duty appeared at the time.