And for some reason a few years later they republished it in only 7, which is just as insane (they literally cut in the middle of the 5th volume).
This has resulted in many larger tomes being split up when translated to French - for example, the first 5 (English/Original) volumes of A Song of Ice and Fire are sold as 15 (translated to French) books in total : https://fr.wikipedia.org/wiki/Le_Tr%C3%B4ne_de_fer#Publicati...
I am also very disappointed at how often French publishers seem to decide that they can chop up these stories willy-nilly without it degrading the quality of the art (re-)productions that they are selling us.
The purpose of the law is to have the same price for a book in every bookshop (with a 5% discount possible). This was supposed to help small booksellers, who could not compete against big corporations. And it kinda worked, as there are more than 3500 independent bookshops in the country.
The split up is not linked to the uniform price, I think it's more a cultural thing.
and now they've updated it to say you can't offer delivery for less than 3 euros...