Director Jacques Deray’s thriller, “La Piscine,” explores issues of sexuality, jealousy, and wealth against a deceptively lush, sun-drenched backdrop. The precursor to Luca Guadagnino’s 2016 remake, “A Bigger Splash,” this 1969 film stars some of France’s most celebrated actors — Alain Delon, Romy Schneider, Maurice Ronet and Jane Birkin — who variously intertwine and withdraw from one another (violently) as the narrative moves forward. The wardrobe, replete with tiny swimsuits, crochet dresses, and paper-thin cover-ups, was designed by André Courrèges only a few short years after his time at Balenciaga.