The French army in WW1 did basically what the Russian one did in WW2 - bleed the German army dry, albeit with more casualties themselves. No other power inflicted more KIA on the Germans than France. They didn't do that with BB guns.
Everyone talks about Stalingrad. At Verdun the Germans had 337,000 casualties.
Today, Stalingrad is renamed Volgograd and is a thriving city of over a million people. Roughly 1.8 million soldiers (all sides) were killed, wounded or missing at Stalingrad (about 800,000 total killed), but the land was largely remediated enough post-war that life carries on. the fighting was also pretty concentrated.
Verdun is a whole different matter. Roughly 1 million solders were killed, wounded or missing spread over a massive trench system, but the situation was compounded in that roughly 1 in 4 artillery shells failed to explode, and at least 1/4 of those shells are thought to have been gas shells. (about 300,000 casualties were deaths)
The land was so contaminated by chemical warfare that even 100 years later, nobody lives there and the French government estimates it may take up to another 800 years to clean up the battlefield due to the sheer volume of unexploded ordnance at Verdun. There are walking tours where you literally cannot wander off a 1m wide path for fear of being blown up or gassed, even today.
Today, only about 18,000 people live in Verdun and the countrysides around the city is effectively uninhabited, littered with the remains of completely abandoned villages inside a "red zone".
The Douaumont Verdun ossuary alone holds the remains over over 130,000 "unknown soldiers". You can actually go in an see the bone piles. It's sobering, and similar in the French psyche to how we feel about the Vimy memorial.
690 million people fought in WW2 and about 25.5M soldiers died - or 3.7%. Only 65 million people fought in WW1 with roughly 9.7 million military dead - or 15%. It was far more hazardous to your health to fight in WW1.
Stalingrad deaths as a percentage of total WW2 military deaths: 3%. Verdun deaths as a percentage of total WW1 military deaths: 3%.
As a percentage of deaths compared to the size of the conflict, the two battles are about equivalent. In terms of lasting impacts to the ground on which it was fought, Verdun remains the worse of the two conflicts.
