Jean-Yves Perrier <perrier@nagra-kudelski.ch> writes:

> But when I open it in my nnfolder:archive group, i see \201é and so on (MULE
> feature...) 

Hm.  I'm unable to reproduce this bug.

> I have Emacs 20.3, pGnus0.13 & no other stuff to do MIME coding (no TM,
> nothing...)
> Note : I have (standard-display-european t) in my .emacs

I use the same.

Is it possible that your Emacs does some extra de/encoding of your
nnfolder folders?

-- 
(domestic pets only, the antidote for overdose, milk.)
  larsi@gnus.org * Lars Magne Ingebrigtsen