This article is from the German Genealogy FAQ, by Jim Eggert EggertJ@crosswinds.net with numerous contributions by others.
The German central government conducted censuses in 1871, every five
years from 1875 to 1910, 1919, 1925, 1933, 1935 (Saar), and 1939.
West Germany had censuses in 1946, 1950, 1961, 1970, and 1987. East
Germany had censuses in 1945, 1946, 1964, 1971, and 1981. Except
for the 1939 census, these censuses are not useful for genealogical
purposes; available data are of a statistical nature only.
Each of the states conducted their own censuses at other times.
Some of these censuses are available via your local LDS FHC and
are quite useful genealogically.
The central German census authority can tell you if certain
censuses exist and where they can be found:
Gustav Stresemann Ring 11