NO ROOM AT THE INN: Plaza Athénée, another landmark Paris home-away-from-home for the fashion set, is slated to close for renovations during ready-to-wear season this fall. The hotel, which celebrated its hundredth anniversary earlier this year, will shut its doors on Oct. 1 for eight months in order to carry out an extension, incorporating into the edifice three adjacent buildings acquired by owner Dorchester Collection. The partial restoration will create six new guest rooms, eight suites, a ballroom and two event spaces, and also involves the renovation of the Alain Ducasse restaurant and the hotel’s famous bar. It follows the closures of the Ritz Paris and the Hôtel de Crillon, both two-year renovation projects.