I have the Medard Ferrero and the Galiano Methode books and can recommend the Galliano.
The Ferrero is purely classical, very old fashioned, and difficult to follow if your French isnt at a high level.
The Galliano is very well laid out and is easy to follow. It doesnt go into music theory but concentrates on playing, starting with a few pages on holdiing the instrument and right and left hand keyboard layouts. It then goes straight on to simple excercises for both left and right hands starting with one finger excercises, then two and so on. Later on there are simple pleasant tunes. All excercises and tunes have the fingering - above for cba and underneath for piano. The first thing I did was to tippex out all the piano fingering as I had enough problems trying to read the music, remembering where the buttons were and then trying to read which finger to use.
It is about 110 pages long plusyou get a cd of all the excercises and tunes, so quite substantial.
I got mine second hand for the equivalent of £10.24 from Amazon France. It had previously been used with a Tutor who had made pencil comment on about 20 pages, which is probably why it was so cheap. I had originally planned on rubbing out all the comments, then realised that the teacher had put them there to help the student so I left them and make use of them myself.
I assume you need a CBA tutor and can recommend this one. If it is for piano accordion there are hundreds to chose from.
Hope this helps. kind regards, Ian