If you provide Unicode code points, you will get Unicode code points.
How can I "get Unicode code points"?. Code points is an abstraction, it's an internal Perl thing. It must produce a bunch of bytes. Yes, some codepoints can be packed into a single byte. And this is what Perl does. Call it what you will.
perl -e'print pack "C*", 0..255;'
perl -E 'say "Français"'
That prints bytes as it recieved them from bash: 0x46.0x72.0x61.0x6e.0XC3.0XA7.0x61.0x69.0x73. On the other hand
perl -E 'use utf8; say "Français"'
That prints garbage instead of 'ç'. The bytes are 0x46.0x72.0x61.0x6e.0XE7.0x61.0x69.0x73 and my terminal cannot display 0XE7.
It's just that the latin-1 encoding of the first 256 code points is itself.