According to the 2004 International Dance Directory, the World Championships were held by Camille de Rhynal in Paris from 1909 until 1939. Apparently, they did not become "official" (whatever that means) until 1936, and seem to have only included Standard Ballroom (no Latin).
The International Dance Directory is a good source of information which includes a list of world and U.S. professional champions from 1914 through today. It also includes a very thorough directory of professional and amateur dancers, studios, and places to go dancing around the world. Everybody should have a copy. More informatoin is avaliable at
www.dancedirectory.com.
Regards,
Jonathan Atkinson
www.ballroomdancers.com