Hello there's a french patch for database that translate all items, quests, PNJs and all other in french.
This database is called UDBfr.
First you have to set the original database from UDB or YTDB as you like en then apply two sql file, one on mangos database and the second on scriptdev2 one.
The svn for this database is
http://udbfr.googlecode.com/svn/
1. Apply in 'trunk' folder the sql file called 'Prepare_locales_tables.sql' on mangos database
2. Unrar and apply the 2 sql files in 'Full_DB', one on mangos and the other on scriptdev2
3. Apply again 'Prepare_locales_tables.sql' on mangos
I advice you to reset the cache of wow game.
Have fun