MuSaMa, le musée du Savon de Marseille

This guide to MuSaMa, Marseille's soap museum, follows chemist François Merklen, an Alsatian who came south to work at a soap works on Rue Sainte and set out to end centuries of fraud in how Marseille soap was made. It traces his years of testing batches, building on the chemistry of Eugène Chevreul, and the standard he published in 1906 for what counted as a genuine bar. You'll hear how that same standard clashes with most of what is sold under the Marseille soap name today. Look for the cauldrons and stamps that walk through his process on your way through the workshop.