The rifled bore was a major change in military operations, obviously, followed not long thereafter with rapid firing breech loading rifles and cartridges.
The French 75 was a significant development, as were of course "tanks", called "Char" in French (after chariot) and panzer in German.
We got to tour part of the Maginot line. Every tiny village in France has an obelisk with names on it from those KIA in WW I. I've been in tiny places where they had 50-60 names on the memorial. The French lost almost the entire generation. By 1935, their demographics were horrible, and Maginot realized he needed fortifications to enable fewer men to man a longer area between France and Germany, the actual border. The line of course "worked" on a tactical basis. The French strategy was to fight the war on the defensive AND in Belgium, as northern France was heavily damaged in the first war. They adhered to that concept, fine concept as it was, except that the Germans (Manstein) had other ideas.
Had the Germans continued with their modified Schlieffen plan, it's likely the war in France would have lasted quite a bit longer. Make sure the Right is strong!