New evidence is provided for a grammatical principle that singles out contrastive focus (Rooth 1996; Truckenbrodt 1995) and distinguishes it from discourse-new “informational” focus. Since the prosody of discourse-given constituents may also be distinguished from discourse-new, a three-way distinction in representation is motivated. It is assumed that an F-feature marks just contrastive focus (Jackendoff 1972, Rooth 1992), and that a G-feature marks discourse-given constituents (Féry-Samek-Lodovici 2006), while discourse-new is unmarked. A crucial argument for G-marking comes from second occurrence focus (SOF) prosody, which arguably derives from a syntactic representation where SOF is both F-marked and G-marked. This analysis relies on a new G-Marking Condition specifying that a contrastive focus may be G-marked only if the focus semantic value of its scope is discourse-given, i.e., only if the contrast itself is given.