It created a massive population of smallholding landowners, which replaced the previous system of tenants and peasants tied to the land; and since so many of them were landowners, and so many attempted to keep the property a) in the family and b) large enough to be worthwhile, they had a strong disincentive towards having as many children as possible because it could split the inheritance.Were the inheritance laws really that devastating to French demographics? I don't know much about these laws, how long were they in place?
The laws stipulated that the peasants had to pay compensation for the lands they acquired, but in reality this never happened and it was scrapped in 1793. After that, it was more a fait accompli than a law on the books that continued in effect as revolutionary France expanded.
I don't think the land-tenure laws would be extended to annexed territories, especially because it would provide a lot of motives for the landholders to oppose the annexation in exchange for creating a new class of potential troublemakers, as the now-landowning-peasantry became almost immediately after they got their land in the 1790s. I think it's more likely that the rural population will resemble OTL's trends, as far as peasants being pushed off the land they tend but don't own by land concentration.So you're wondering if French Revolutionary land-tenure laws would apply to annexed Belgium and Rhineland? Probably would.