50 per cent offered by the writer from France yet to be translated (6)
I believe the answer is:
moiety
'50 per cent' is the definition.
I can't judge whether this definition defines the answer.
'by the writer from france yet to be translated' is the wordplay.
'by' means one lot of letters go next to another.
'the writer from france' becomes 'moi' (I am not sure about this - if you are sure you should believe this answer much more).
'to be translated' indicates anagramming the letters.
'yet' anagrammed gives 'ety'.
'moi'+'ety' is 'MOIETY'.
'offered' acts as a link.
Can you help me to learn more?
(Other definitions for moiety that I've seen before include "Part" , "Fair portion" , "Oy! Time for a half" , "A legal sort of half" , "One of two equal parts" .)