Va Savoir (Who Knows?) (2001) on Netflix

Plot summary

Camille, a French actress, has spent three years in Italy and comes back to Paris with the Italian-language Pirandello production that her husband Ugo runs. Meeting Pierre, the lover she left behind, makes her uneasy, and she seeks him out in a park, where she learns he is still writing a doctoral thesis about Heidegger. Ugo keeps to himself a search of his own: he wants an unpublished Goldoni play. In a library he meets Dominique, who points him toward a collector. Through that introduction he reaches the private library of Dominique's mother, Madame Desprez, who lets him look around but tells him that books have gone missing from it.