The press release for there 22 July firmware release:
http://www.ectaco.com/news/8638/
lists support for some of the UTF-8 encodeable languages/fonts but French isn't listed.
There is no mention of dictionary support for these, though.
The existing dictionaries work both ways. eg... Eng>Rus or Rus>Eng but I don't have any
non-English files on my JBL at the moment to see how it works if you are starting from one of the other supported languages.
Luck;
Ken