BUG #4332: ERROR: invalid byte sequence for encoding "UTF8": 0xc3

The following bug has been logged online:

Bug reference:      4332
Logged by:          Maxime Carbonneau
Email address:      manitou@maikan.com
PostgreSQL version: 8.3.3
Operating system:   Mac OS X 10.5.4
Description:        ERROR:  invalid byte sequence for encoding "UTF8": 0xc3
Details:

Doing "SELECT to_tsvector('pg_catalog.french', 'ecole');" in the psql
console, I get
ERROR:  invalid byte sequence for encoding "UTF8": 0xc3
HINT:  This error can also happen if the byte sequence does not match the
encoding expected by the server, which is controlled by "client_encoding".
I did some modification on the file
"/usr/local/pgsql/share/tsearch_data/french.stop" to realize that the letter
'à' brings the error.
SHOW client_encoding; => 'UTF8'