During the Franco-German war of 1870-71 mail was brought into Paris in Boules de Moulins, “milled balls” of zinc 13cm in diameter by 20 cm in height. They could hold between 500 and 800 letters. The service began on January 4, 1971, but none of them reached Paris before the city surrendered on January 28 and the service was discontinued on January 31. 35 Boules were retrieved from 1871 until 1982. The courts have determined that the letters they contained belong either to the heirs of those who wrote them or those to whom they were addressed.
     In 1979 a stamp with an open Boule de Moulins and a map of the course of the Seine River between Bray-sur-Seine and Paris. On the stamp Paris is clearly identified, while on the cache the city is indicated by an irregular black circle. The First Day cover also shows an open boule, and on the cancellation, the outline of a boule and also a Simoun mail airplane representing the companion stamp.