I just found some information about the narrow no-break space
, which is more recent than the thin space and presumably more promising for French writers and about its font support. Here.
Like presumed, ADE is flagging it with a question mark. Even using a supported font (TNR), on my -old- PRS-505, I get the same question marks.
So, if I prepare an EPUB with these narrow spaces, it seems it will be moreless the same as with the thins spaces. Only the "new generation" of e-readers seems to be able to transcribe them correctly. French will have to wait a little...
Or did I miss something?