There is a French edict of July 25th, 1831 that regulate that letters from suspect neighbouring countries in the east, have to be disinfected due to the cholera. Letters disinfected in Germany are usually perforated with pinholes done by a rastel or an awl while letters disinfected in France are usually slitted with a chisel or blade.
Database: Please add further letters disinfected at the eastern border of France.
Givet: 10.08.1831 – 07.11.1831
Forbach: 17.08.1831 – 24.02.1832
Strasbourg: 15.08.1831 – 09.11.1831
Hüningen: 26.11.1832 (triple disinfected letter from Constantinople)