While some sources claim it is a modern invention, Encyclopedia Brittanica claims that Romans already differentiated right from left footwear, see shoe. Look also at these sandals from Ancient Egypt.
Looking on the web, it is a mess as is full of blog/news articles without sources pointing to somebody in the 1800s. For English sources it is sometimes claimed that left/right shoes were invented somewhere in Philadelphia, Pennsylvania. Some French sources claim that it was Alexis Godillot, an industrial man that introduced some famous godillot boots that differentiated left from right.
The closest source I got so far was from German Wikipedia (which also confusingly) claims that it was a German academic called Georg Hermann von Meyer who apparently advocated for chiral shoes under a work (yet to be found) called Über die richtige Gestalt des Schuhes (1858). Some of von Meyer's work is freely available (translated) in Wikisource, here. This observation implies that about 1858, chiral shoes were at least as popular as symmetrical shoes.
Anyway most of the stories seem like oversimplified anecdotes (including Lebesgue's story) and I don't think there is a clear source but I will update this answer if something more concrete comes up.
Edit: Conifold provided this academic paper by A. Swallow History of Shoes (1987), which does not cite any of the men above but clearly states that chirality in shoes has been reintroduced many times in history depending on the kind of footwear.