Problems with special character rendering

Hi,
I have a little problem with psql
with 8.4.6 ,
  select E'é\fr';
gives :
 ?column?
----------
 é\x0Cr
(1 ligne)

whereas with 8.1
select E'é\fr';
gives
 ?column?
----------
 é
  r
(1 row)

I tried changing both client/server encodings, etc.
Why does 8.4 not render \f as a form feed ?

Thanks,
Thomas