I found a way to see "martin aurélie" user directory!
You "just" have to start Knoppix in French using "knoppix lang=fr"
I do not know why this directory is not showing in standard but in French it does!
I succeed to backup all my data!
...KNOPPIX is really GREAT

Do you have any idea how to be able to read accent in "standard" (English) Knoppix

Thank you for your support,
Henri

PS:I am actually a Windows user but for my next config I will use Knoppix or Debian (I do not know yet..)