Build.xml needs to specify encoding for call to YUICompressor
YUICompressor is used to generate the compressed .js file. It needs to specify the char encoding of UTF-8 otherwise it will default to the host computers default encoding.
To see the problem, search for "SelectionPanel" in the resultant fusionSF-compressed.js file. The second occurrence of this will have a corrupt French string. Applying the attached patch will fix the problem. All I did was add the charset argument and specified UTF-8; I don't know ant so I don't know if what I did was correct or not, but when I ran it, the compressed file looked good.
The patch file changes the charset in two other places where YUICompressor is used; I'm not sure if these two other places should have the change or not.