Easiest way is probably to use File::Slurp.

Here's an untested example:

#!env perl

use strict;
use warnings;

use File::Slurp qw/read_dir/;

my $Dir_Prefix = '../../dir1/dir2';
my $File_Path = 'dir3/filename';


MAIN: {
    my @files = read_dir($Dir_Prefix);
    foreach my $file (@files) {
        -d $file or next;
        if (-e "$Dir_Prefix/$file/$File_Path") {
            print "$file\n";
        }
    }
}
[download]

Update:Updated from a File::Find example.