C'est du pipeau !

5. C'est du pipeau !
pronounced more or less: say dew pee po
The stress goes on the last syllable, "-peau": C'est du piPEAU !
Variant: C'est pas du pipeau ! / Ce n'est pas du pipeau ! These are simply negative forms of the expression, meaning something akin to: "And that's not just whistlin' Dixie, folks."
"Un pipeau" is a reed pipe (tin whistle) or a bird call.
Literal translation: "It's a bird call." / "It's a tin whistle."
Implications: C'est du pipeau implies that whatever was just said isn't true or at best a stretch of the imagination. It's roughly equivalent to the American English expressions, "what a load of rubbish" or, a bit more outdated, "it's strictly for the birds." It's sometimes used as well to indicate that, in the user's opinion (always the favored perspective), what is being referred to as "pipeau" is inconsequential, no big deal, about as important as...well, let's see...a tin whistle.
Remarks: This is a familiar, fairly high-frequency expression, in no way vulgar (sorry to disappoint).

Example One: You walk into your dining room and nearly drop to the floor when you see that someone has carved his initials into your beautiful mahogany dining table. A blood curdling J'hallucine !  escapes your lips. You suspect one of the kids in the household, and by "suspect," I mean that you're sure. Not having good parenting instincts, you call all the kids into the room in hopes of exposing the culprit and forcing a tearful, guilt-ridden confession. They all deny the act. Dumbfounded, you say: C'est du pipeau !!!! Mais j'hallucine ou quoi ?!!!
To no avail, of course. Eh bien !

PS: this example crosses cultures with no problem whatsoever. Just ask my brother, JS.

Example Two: "La Tour Eiffel bio, c'est du pipeau" ["an organic Eiffel Tower, yeah, sure, you betcha...not!"] That's what all the buzz was back in 2009 when the French were preparing, in celebration of the 120th anniversary of the Eiffel Tower, to re-paint the giant according to the organic norms set up for 2012. In fact, the paint used was identical to the paint used in 2001, no lead, but plenty of solvents, so... c'est du pipeau !