You can fix the output by enabling the correct IO layer for the output: 
binmode *STDOUT, ':encoding(UTF-8)';

[download]

Perl JSON modules keep the strings in parsed structures as characters, but when serializing to JSON strings, they use bytes and UTF-8 encoding.

Update:

According to the specification, JSON doesn't use entities, but it can use the \uXXXX notation, so instead of using HTML::Entities, you can try

sub convert {
    my ($s) = @_;
    $s =~ s/&#x([[:xdigit:]]{4});/\\u$1/gr
}

my $entities_json = '{"school":"Eötvös Loránd Uni
+versity"}';
my $converted_json = convert($entities_json);

print "Original JSON: [$entities_json]\n";
print "Converted JSON: [$converted_json]\n";  # [{"school":"E\u00F6tv\
+u00F6s Lor\u00E1nd University"}]

my $decoded_json = decode_json($converted_json);

binmode STDOUT, ':encoding(UTF-8)';
print "School: " . $decoded_json->{'school'} . "\n";  # Eötvös Loránd 
+University

[download]

map{substr$_->[0],$_->[1]||0,1}[\*||{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]

In reply to Re: Converting entities in JSON context by choroba
in thread Converting entities in JSON context by Anonymous Monk

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