Well, not exactly for dancing! These are called galoches and are a work boot worn over a regular shoe by French country folks in the 19th and early 20th centuries. The sole is made from a thick, hard piece of wood. The top, which is nailed on, is hard-tanned leather that softens (but not much!) as it laces up to above the ankle. They look mighty uncomfortable to me, but I'm sure they were very practical for the paysans working in barns and fields. Dedou remembers wearing them himself as a youth.
Look closely and you'll see a strip of iron nailed around the toe of the sole of each boot. Looks kind of like a horseshoe. My guess is this helped give the wearer a bit of traction on slippery surfaces and uneven stone floors. Be a bit careful how you talk about your galoches, though. Galoche is also a slang term for French kiss. The things one learns on Wikipedia!