Pièce de théatre "un air de famille"

Philippe is a successful man. An executive in a company that also employs his sister Betty, a fiercely single woman, he is married to Yolande. Together with their mother, they meet one Friday evening in the sad bistro run by Henri, the older brother, to celebrate Yolande's birthday.
But things don't quite work out as they should. And when Denis, the waiter, interferes in the family business, the festivities turn into a settling of scores.