Haven't really a clue, but Tandy is/was the trading name for Radio Shack in most parts of Europe - maybe "Le Tandy" was theirs for Le Market Francaise?
Just a thought, looks very interesting at least - also you could ask Paul Wirdnam of the "Electric Watches" website, (linked on the links page) who is a fount of all knowledge regarding various electrically powered movemnets - he may know of this - or be pleased to know of it.
