Locales problems with debian sarge3.1

Hello,

I saw lot of topics treating about the subject, but nowhere i found
real solutions. Has the bug been fixed?

# set >
LANG=fr_FR
LANGUAGE=fr_FR:fr
LC_ALL=C
LC_MESSAGES=C

Before initialising DB I fixed these variables :
(I don't use -E option of initdb)

export LC_ALL=C
export LANG="fr_FR.UTF-8"

Before launching application I fixed these variables :

export LC_ALL=C
export LANG="fr_FR"

Do i have to fix environment variables in postgres.conf?

And eventually , when attempting to DB , I have this:

waiting for postmaster to start....FATAL: invalid value for parameter
"lc_messages": "fr_FR.UTF-8"

Who ask lc_message to associated to fr_FR.UTF-8 ?
Is there a way to make it valid value?
Have I made wrong variable association?
Is there a generic option to make postgres to work?

Thanks

Regards,