I can get that output with:
LC_ALL=C tree -A
tree thought that 0303 and 0251 were not valid characters (or sequence of character in your locale).
However that is valid in UTF-8 locales where
é and in iso-8859-1 or iso-8859-15 (the two common single byte per character charsets that are common in French speaking countries) where
So, here that suggests you're in a locale where the charset is defined only for the first 128 byte values like ASCII is like in the C locale.
You could tell
tree that your charset is UTF-8 or iso-8859-15, and then it would not translate those 0303 bytes to
locale -a will tell you if there's a locale on your system with a UTF-8 charset. Then you can pick one like
But then, whether it's going to be displayed properly or not will depend on what your terminal emulator understands. If it's not configured to display UTF-8 characters, it won't work.
If your terminal emulator is able to display iso-8859-1, you could make
tree display UTF-8 and convert that with
LC_ALL=fr_FR.UTF-8 tree | iconv -f UTF-8