When I visited the Breton village of Guenroc, I was really there for its distinctive carved chimneys. However, I also found an old sign, rusted and half-obscured by foliage but still clinging to the wall. It advertised Cacolac, which an internet search showed to be a chocolate milk. It is still manufactured today, but I had not noticed it in the shops. The sign soon slipped out of my mind.
Happily, I was reminded of it when I chanced upon a post on Invisible Bordeaux. The drink is Bordelais, perhaps inspired partly by the availability of cocoa beans in the city's docks; created in 1954, it is still made to the original recipe. There's more to the story - do go and read it; best of all, my curiosity is now satisfied. There's also a new item on the shopping list for my next visit to France!