Is the director French?  Is Joan not a French heroine?  If the answer is yes to both questions, then I have a hard time understanding why Besson makes her "confess" that all her great deeds were a mistake.  It doesn't bother me to interpret Joan of Arc as a lunatic - for all I know she may have been schizophrenic indeed!  (What else makes you hear voices?)  What I don't like is the notion that Joan herself lost faith in her own cause, questioned her own motives and regretted what she did, as apparently Besson makes her do at the end.  That's not my idea of a heroine or hero.