One of the really big supermarkets. If my memory serves me, there is a huge branch of Intermarche on the outskirts of Carcassonne, which may well have what you need -- it has branches that specialise in things like DIY and furniture, too, so if the main store doesn't have it, one of those may. A play pen is a parc pour bebe, a cot is a lit d'enfant or a petit lit. (You probably already know this!).

Intermarché Hypermore
ZI du Pont Rouge
11000 Carcassonne, France
04 68 71 07 11

http://www.intermarche.com/magasin_accueil.aspx?itmid=11299
NB I drew a blank on their website for playpens and cots, but their search engine is rather basic.

Otherwise, there's a Conforama (large furniture chain, whose website promises baby furnishings)

CARCASSONNE
ZAE LA FERRAUDIERE II
RUE PAUL HENRI MOUTON
11000 - CARCASSONNE*
Tél : 08.26.08.10.12
Fax : 04 68258469

all right, I didn't believe the first person who said you found baby cots in supermarkets in France, but apparently I should have. And I have no French at all save hello, goodbye, and thank you, so I didn't know that about the names. Thanks. :)

Whyyyyyy is it that whenever anyone I know goes to France, they don't know French, but I never get to go with my 8 years of middle+high school and 1 quarter of community college conversational French? #firstworldproblems :)

I don't know, but if you wanna hop on a plane and come play translator, the couch in this place folds out too... :)

If there's a next time and more warning, I might consider this. :)

See?

yes, yes, i see, i fling myself on your mercies! but seriously, *supermarkets*? :)

You can get *everything* in French hypermarkets :-). (Seriously, they have great clothing, wonderful glassware, and, well, everything. The only thing I ever remember not finding in one was dental tape, as opposed to floss, and that was in a smaller one that was only really a big supermarket as opposed to the true hypermarche.)
Glad to be useful.
The marquis says to tell you that you have some of the finest castles in France near you. Queribus is possibly a bit daunting with Mr D (it involves a lot of walking uphill) but he recommends Perpeyteuse. http://en.wikipedia.org/wiki/Peyrepertuse

holy crap, that's a magnificent castle. O.O

And we got a cot! Thank you! <3

It's a wonderful castle. It may be one of the marquis' very favourites.
And yay on the cot!

My mother is off to Canet tomorrow. Is that near you?

Well, by Alaskan standards, yes, but by European standards, perhaps not... Looks like it's about 90 minutes away. :)

Hope you find the cot and learn some french, write some book, relax and chill and have a good time - IN FRANCE WITHOUT ME!!

"chill" is clearly not on the menu, she said, staring in horror at the weather forecast...

We were in the neighbourhood of Carcasonne last week, there's a little town called Castelnaudary not far from Carcasonne where you should be able to find something
here's the link
http://www.new-baby-castelnaudary.com/index.htm