http://Mediawiki.org is a multilingual wiki. All the language pages are in one install of Mediawiki, so there are no special facilities to manage translation. They use subpages to connect the translation sets.
http://www.mediawiki.org/wiki/Project:Language_policy
http://www.mediawiki.org/wiki/Project:Language_policy/fr
http://www.mediawiki.org/wiki/Project:Language_policy
http://www.mediawiki.org/wiki/Project:Language_policy/fr