The Secret of Polichinelle(1997)

After a New Year's Eve party, 30-year-old fashion designer Rebecca (Nathalie Schmidt) awakens alone in a strange automobile. Later, during a routine visit to her gynecologist, she learns that she's pregnant. Unable to recall anyone responsible, she attempts to find the father as she treks through Paris streets, quizzes her girlfriends, and visits a Belgian detective. With few leads, her search drags on for months.