From the Internet web site of the American Central Intelligence Agency an archived item.
"The Early Development of Communications Intelligence" [COMINT]
CIA HISTORICAL REVIEW PROGRAM courtesy the German original author Wilhelm F. Flicke.
Radio intercept and intelligence the Great War [WW1].
"The German command missed its greatest opportunity during this same [1917] spring. The French army in its unsuccessful attack on the Aisne and east of Reims had suffered such severe losses that its morale was badly shaken. Intercepted messages revealed that there was mutiny in numerous army corps, that individual soldiers and whole units were leaving the front or deserting to the enemy. In this situation they could not have resisted a German attack. But the incredible happened: the German command, seeing in this situation a parallel with the Russian front, expected the French power of resistance to collapse without any further German action. It missed the chance which was never to return. While the Germans waited for capitulation Petain resumed command, the crisis came to an end, and the French front stood firm again."
THE MUTINY OF THE FRENCH ARMY WW1!
French troops in the aftermath of the unsuccessful Nivelle Offensive no longer willing to go on the offensive. Over-the-top and toward the German denied by mutinous action. Defense still thought to be proper but further fruitless offensive action by French troops now out of the question.
MY UNDERSTANDING OF THESE EVENTS HAS ALWAYS BEEN THE GERMAN NOT EVEN AWARE THE FRENCH TROOPS HAD MUTINIED! THIS PERCEPTION OF MINE APPEARS TO BE WRONG.
German senior commanders content to wait things out. Allow the mutiny to create conditions where the French government would have no option but to negotiate a surrender with terms favorable to the German.
Total collapse and French surrender did not occur. But YES knowledge of the mutiny was KNOWN to the German and thanks to radio intercept.
coolbert.