Here is the 4.5.rc2 French translation.
Since 4.5.rc1 there is a new property file (ZhMsg.properties) with more than 500 lines. I'm still translating it, so many labels in the new features will be in English.
As usual, you can download the translated files attached below plus a tar file with the date zimlet, the spell check patch, and an installation script, from http://files.whitehatmail.fr/ (user invite, password invite).
The spell check works better, but still has some bugs. I have to do some more tests before posting it to bugzilla.
Otherwise, the upgrade from 4.0.4 works smoothly and, personnaly, I like very much the new GUI layout.