I tried to decode a MIME-encoded message with MIME::Tools, and got the body decoded from quoted-printable to bytes and accessible via MIME::Body methods. To get the unicode characters I needed to do one more decoding step and decode my message body from bytes to characters using Encode module.

Approaching your example,

use MIME::Decoder;
use Encode 'decode';

# only for this particular case I will decode QP manually
my $d = new MIME::Decoder 'quoted-printable';

# usual way of obtaining bytes decoded from 
# QP/Base64/7bit/other content-transfer-encodings
# is to use MIME::Body methods

# encode unicode characters to UTF-8 on printing
binmode STDOUT, ":utf8";

# open an in-memory filehandle
# since MIME::Decoder only supports filehandles
open my $fh, ">", \(my $bytes);
# decode the quoted-printable
$d->decode(\*DATA, $fh);
# decode the bytes
my $characters = decode 'utf-8' => $bytes;

# prove having 1 character, not 4 bytes
while ($characters =~ /(.)/g) {
 printf "%s is unicode character %x\n",$1,(unpack"W",$1);
}
__DATA__
=F0=9F=98=B3
[download]

� is unicode character 1f633
[download]

More info at perlopen, Encode, perlunitut, perluniintro, perlunifaq.