Paris point
The Paris point is a unit of length defined as ⅔ of a centimetre. It is commonly used for shoe sizes in Continental Europe.
The unit was invented by French shoemakers in the early 1800s. Its origin probably lies in 2/3 of a centimetre being very close to a quarter of an inch; a French inch pouce-roi is around 27 mm, a quarter of that is 6.7 mm, close to 6. mm defined for the Paris point.
