I'm familiar with the UPSM enterprise (brand) and its details (i.e. saponified plant oil/s, no animal-sourced material, made in Marseille region, cauldron method, fragrance-free, no dyes/preservatives).
What detail does Rampal Latour purportedly not respect?
(There's also AFSM - Association des Fabricants de Savon de Marseille.)
From what I can gather on Rampal Latour's website:
"notre savon de Marseille contient davantage de glycérine hydratante naturellement produite qu'un savon de Marseille classique "
Basically they are saying their soaps contain more glycerin than traditional SdM ...so is this glycerin added or left naturally ?
"Tous nos parfums sont 100% naturels. Par exemple, notre savonnette Olive-Lavandin contient de l'huile essentielle de lavandin, cultivée et distillée en Drôme provençale. Reconnu pour ses vertus antiseptiques et apaisantes, le lavandin parfume délicatement la peau par ses notes provençales ensoleillées. Concernant la couleur, nous n'utilisons que des pigments minéraux."
They admit to using perfumes, essential oils and dyes in their soaps !
If you look at the 11 members of AFSM - Association des Fabricants de Savon de Marseille they are pretty much small shops that process or reprocess soap shavings and flakes.