Bordel!

Today, synonyms of "mess", most acceptable ones first, most familiar ones last. The top of the list would be more likely to be used with verbs like "mettre" (to put), the others with its slang equivalent "foutre":
(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"