Bordel!
(un) désordre
(une) pagaille
(un) chantier
(un) fouillis
(un) tohu-bohu
(un) bazar
(un) souk
(un) barnum
(un) fourbi
(un) foutoir
(un) binz
(un) dawa (not sure this one made it to the dictionary yet)
(un) bounsa (this one is used by the younger generation, don't ask me)
(un) boxon
(un) merdier
(un) bordel (a classic, my personal favorite)
E.g. "Il a mis la pagaille" = "Il a foutu le bordel" = "he made a mess"