Rare and early "Floating Curve" loveseat or sofa by Vladimir Kagan. Loveseat is a smaller version of model #176SC. Sofa is from a single-owner collection of early Vladimir Kagan furniture (please see the other pieces listed online).
Reference (similar form): The Complete Kagan- A Lifetime of Avant-Garde Design, Vladimir Kagan, ppg. 114-116, 264.