I am looking for the exhibition poster of the photographer Guy
Bourdin's exibit in the Jeu de Paume in Paris. The exhibit was in the
summer and fall of 2004. I had the poster and lost it and am trying to
find it for sale again. Where can I find this?

Is the poster you're seeking pictured here? http://guybourdin.org/tour/tour3.html

yes that is exactly the one. do you know where i can buy another one?

Hi again. I can't find the poster for sale but at this site:
http://guybourdin.org/tour/
there is a contact email address which you could try asking them.
Failing that, have you contacted the Musee Jeu de Paume directly? They
might be able to help you. http://www.jeudepaume.org/ (Note that it's
in French though.)

Good luck. 

P.S. I rang the National Gallery of Victoria here in Melbourne
Australia (they recented had a Guy Bourdin exhibition) and asked them
where to obtain a poster. They suggested a store here in Melbourne
that might be able to help you out:
http://www.stevenprintgallery.com.au/start.htm or telephone: +613 9429
5996.

I'd love to hear if any of these prove fruitful!