Is that the one he did with Noam Chomsky?
No, it's not his documentary on Chomsky, it's his adaptation of Boris Vian's novel with Audrey Tautou and Romain Duris, filmed in French. It's supposed to come out in the US eventually (or may have come and gone already, I'm not sure) under the tile "Mood Indigo", though the movie didn't perform very well (it got good reviews from specialized magazines that compared it notably to Brazil, and generally bad reviews in the general press) and I don't know if they'll release it in the States after all. That's too bad as being a huge fan of Vian I thought it a really good adaptation and movie, but OTOH it seems to have been badly received by two categories of people: those who read the novel as teenagers and have a skewed memory of the book as some sort of Amélie-type of story with "delightful" fantasy elements, and who found Gondry's vision way too dark (though in truth it's very faithful to Vian, much darker than a first degree read of his Lewis Caroll/Swift/Rabelais like use of nonsense and word plays let believe). Then people who don't know Vian at all generally disliked the movie (it's not an easy one, starting as a romantic comedy full of nonsense and surreal elements, invaded by absurd objects with a life of their own and very suddenly shifting to become a full-on tragedy with existential themes. So I'm not sure an American release would be worth it (or has been worth it), it would certainly be a confidential one as the movie has had zero appeal to mass audiences even in France where the novel is one of the foremost modern classics and Vian enjoys cult status.