#! /usr/bin/perl
use warnings;
use strict;

use utf8;
use Text::Unidecode;

my $input = 'Montréal Centre-ville';
print unidecode($input);
__END__
Output:
Montreal Centre-ville
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If you're reading the input from a file, you don't need utf8. Instead, you should specify the encoding of the file:

open my $IN, '<:encoding(UTF-8)', 'input.txt' or die $!;
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Update: You should consider editing the title. Unidecode fails recognising the accents, it wouldn't print them even if it worked.