use warnings;
use strict;
use Encode;
use HTML::Entities;

my $str = "\xe2\x80\x9cquotes\xe2\x80\x9d";
print "Is $str UTF-8? ",
    Encode::is_utf8($str) ? "Yes!\n" : "No...\n";

$str = decode("UTF-8", $str, Encode::FB_CROAK);

binmode STDOUT, ":encoding(UTF-8)";

print "It's still $str... UTF-8 now? ",
    Encode::is_utf8($str) ? "Yes!\n" : "No...\n";

my $wide_chars = "\x{201C}quotes\x{201D}";

print "How about this version: $wide_chars? ",
    Encode::is_utf8($wide_chars) ? "Yes!\n" : "No...\n";

print "Entities: ", encode_entities($str), $/;

__END__
Is “quotes” UTF-8? No...
It's still “quotes”... UTF-8 now? Yes!
How about this version: “quotes”? Yes!
Entities: “quotes”