The Diary of Lady M

The Diary of Lady M is a 1993 Swiss drama film directed by Alain Tanner and written by Myriam Mézières, who also stars. A co-production between Switzerland, Belgium, Spain and France, the film follows a Paris nightclub singer whose affair with a Catalan painter becomes entangled with his marriage. It screened at festivals including Locarno, Montréal, Toronto, London and Istanbul.

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.