The data I'm working with will all be UTF-8, if that makes a difference.

Make sure it's decoded using one or more of the following

use utf8;                            # Treat the source code as UTF-8

use open ':std', ':locale';          # Treat STD* as per locale
use open ':std', ':encoding(UTF-8)'; # Treat STD* as UTF-8

use open IO => ':encoding(UTF-8)';   # Treat files as UTF-8 by default
open(my $fh, '<:encoding(UTF-8)', $qfn)  # Treat a file as UTF-8

utf8::decode(my $text = $encoded_text)  # Treat a string as UTF-8
   or die;
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And make sure the string us stored internally as UTF-8.

utf8::upgrade($s);   # Use UNICODE semantics
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(No need to do use utf8; to use utf8:: functions. use utf8; means the source is in UTF-8.)

If you do those two things, regexp will use UNICODE semantics, so \w and character classes will match accented letters, etc.