As given above, most interesting is "Mastering the French" ("...with the read and play method") Mc Donald and Harley,Batsford Ed., 1997 ISBN 0 7134 5716 3.
The book is ideal for beginners in French Defence (I suppose I have this feeling because it is organized in chapters according to pawn structure and center, like Fine's book "Ideas behind chess Openings").
BUT I guess it will be difficult to find the book, (some years ago, there was a strange affair between Batsford Ed. and some authors ; it was before Batsford being moved into Chrysalys group...nowadays some chess books are published by Batsford-Chrysalis example: Psakhis's books about the French).
Hence, best is to send an eMail first to McDonald to ask for an advice for getting the book.
In french language, "Gagner contre la Defense Francaise" - Evgueni Svechnikov, Ed. Payot, ISBN 2-228-90067-2, is a good starting point for White player (because Sveshnikov advocates advance French). Kosten's book, "The French Advance" is good too ISBN 1-901259-10-2, ChessPress Ed.
If you like gambits as White, "Four gambits to beat the French" Harding,
www.chessdigest.com, ISBN 0-87568-295-2 is your book.
For Black player, Watson's Play The French is most interesting because good explanation of systems (sometimes offbeatean tracks systems)