Usually called the Geneva Protocol, this short arms control agreement was signed at Geneva on June 17, 1925 and was registered on September 7, 1929. It prohibits the use of chemical weapons and biological weapons, but has nothing to say about production, storage or transfer. It was in 1972 augmented with the Biological Weapons Convention and in 1993 with the Chemical Weapons Convention.
External links
Text of the protocol -- http://www.brad.ac.uk/acad/sbtwc/keytext/genprot.htm