Chris Waigl at /ser.ənˈdɪp.ɪ.ti/ presents a "long overdue post on French eggcorns, with an introduction and (in the second installment) a collection of about 40 of poteaux roses". The first example, of course, is the name: pot aux roses (= "pot of roses") is part of a French idiom découvrir le pot aux roses, literally "discover (or uncover) the rose pot", used to mean "to find out what's going on" or "to accidentally uncover a scandal". Since the role of the rose pot in this idiom is fairly opaque, it's not suprising that people often render it (whether jocularly or in error) as (the homophonous expression) poteau rose (= "rose-pink post"), an item whose discovery might in some contexts be felt to be the essence of the matter.
Back in February, Language Hat discussed this idiom, with a variety of scholarly links as well as a reference to the fact that Chris had chosen it as the most appropriate French term for the sporadic folk etymologies that we've come to call eggcorns in English. In a comment on Hat's post, Chris explains:
Posted by Mark Liberman at July 22, 2005 08:42 AM
TLF and the Robert Historique de la Langue Française agree that the original meaning was récipient contenant de l'essence de roses, i.e. a recipient for rose essence or perfume. Découvrir is then understood literally, as dis-cover, take off the cover, which sets the scent free. What I find so attractive about poteau(x) rose(s) (lit. "pink pole") as an equivalent for "eggcorn" is not it is a common misspelling for pot aux roses (it isn't; the substitutions are overwhelmingly jocular, including in film and literature), but that it has undergone the double eggcornification process, just like &ae;cern->acorn->eggcorn. In both cases, the first step has been mostly forgotten, and only shows up as a pinch of folk etymology in the history of the word/expression.