What you think of the Compagnie Philippe Genty depends a lot on how much narrative you require in your drama. Those who need to know at all times why they're watching and where the story is going are advised to satisfy their yearning for theater elsewhere. With its witty optical illusions and ever-changing stage pictures, this Paris-based troupe presents a theater of images, not words--in fact I don't remember a single line of dialogue from Derives, their entry in the 1992 Chicago International Theatre Festival. Instead director Philippe Genty and his company take elements from dance, puppetry, pantomime, silent comedies, fashion shows, and performance art and combine them to create lush stage fantasies; their current work, Forget Me Not (Ne m'oublie pas), feels more like loosely connected dance sequences than scenes in a play--and more like pure, spontaneous eruptions from the unconscious than theater or dance. At the Theatre School, DePaul University, Merle Reskin Theatre, 60 E. Balbo, 902-1500. October 1 and 2: Friday, 7 PM; Saturday, 2 and 8 PM. $20-$40. Friday's show is preceded by a cocktail reception and followed by dinner and dancing for persons buying benefit tickets at $225-$500; for benefit information call 664-3370.