my $data = 'fÃ&¼r'; # so gemeint, wie's da steht
HTML::Entities::decode($data);
print $data;
Encode::from_to($data, "utf8", "iso-8859-1");
print $data;
HTML::Entities::encode($data);
print $data;

use HTML::Entities;
use Encode;
my $data = 'fÃ&¼r'; # so gemeint, wie's da steht
HTML::Entities::decode($data);
print $data, "\n";
Encode::from_to($data, "utf8", "iso-8859-1");
print $data, "\n";
HTML::Entities::encode($data);
print $data, "\n";
^Z
fÃ&╝r
f?r
f?r

D:\temp>perl
use Encode ();
use HTML::Entities ();

local $\ = $/;

my $data = 'f&├&¼r';
HTML::Entities::decode($data);
print $data;
Encode::from_to($data, "utf8", "iso-8859-1");
print $data;
HTML::Entities::encode($data);
print $data;
^Z
f&├&╝r
f&ⁿr
für