A CONVENIENT AND inexpensive place to dine before going to the Opera is Le Tourisme, in the Rue du Helder, a small street that runs between the Boulevard des Italiens and the Boulevard Haussmann. At No. 12, you will find a small, comfortable little cafe \vi:lTe you can sip your aperitif before climbing the stairs to the first floor restaurant. There is an imposing outsize menu card with a long list of dishes to choose from. When I was last there I counted as many as seventeen different Plats du Jour. These included the SpeciaIites de Ia Maison; Cote de Veau Vallee d' Auge, Steak au Poivre Flambe, Cuisse de Lapin a ]a Dijonnaise, Boeuf en Daube, Courgettes Farcies, and Boeuf a la Mode elu Berry.