I'm sure it fucked the birth rate. I'm not aware that it screwed production, although it's an interesting point. France had a total population of about 25 million at the time. In 1813, some of the attrition would have been PoW's and they would have returned to France after the war.
It's an interesting point. Most of the dead would have been in the 18 - 25 age range and you could theorize that they could have been replaced within a generation. This is the age where women pumped out 10 kids and 6 survived to adult hood and the population was increasing anyway over time.
My sister is into family history and all my great g-parents had 10+ kids. It's an interesting area to study. Britain could absorb huge population increases in the 1800's because it was industrializing and urbanizing very fast and had colonies which were climatically suitable for white emigration. France far less so. It remained non urban and agricultural and had no temperate colonies.
In 1812, Napoleon forced Italy, Poland and Germany to supply most of the recruits for the Invasion of Russia and that cushioned the blow to France. OTOH, France was also fighting a totally separate war against Britain and Portugal and a shoddy assortment of make-shift Spanish forces in the Iberian Peninsula which also had a huge attrition rate for the French.
