Checking my understanding of locales

From experimentation and reading the documentation I understand that locale
settings governing the formatting of numbers and dates are only set at the
server and not the client.
For example - the database is initialized in the fr_FR locale. Starting
psql under the en_US locale and executing "select
to_char(1234.56,'9G999D99')" gives an output of 1 234,56 - i.e. the
formatting of the server, not the client.
lking about
I do see some English messages from psql (but also French for anything from
the server).

Can a single database support clients running in different locales from it
for formatting (not talking about ORDER BY here) and if so, how?

Tim