There have been notices on various websites that Jean did not appear in some films for one reason or another, and one mention is the Francois Truffaut film la nuit Américaine (Day for Night). Wikipedia reports that Jean's non-appearance in the film may have been the result of her "state of mind." Jean was still acting and had made The Corruption of Chris Miller a few months earlier, was hoping for an offer for "a film with Michael Caine" (which did not come through), was working on a screenplay entitled Frontière Palace, and then accepted the lead female role in Mousey (also known as Cat and Mouse) by the end of 1973.
It was a great hope of Jean's to work with director Truffaut. She had come close to that realization with Fahrenheit 451, but it was decided two "modest" roles would be played by one actress, with Julie Christie being given that honor. Jean would have gladly acted in a small role because her ego was not such that she demanded the leading female part. Nor would she have demanded top pay since she had not in the past with works she felt were worthwhile.
Regardless, when Truffaut was preparing Day for Night, he tried contacting Jean several times, but to no avail. Rather than "her state of mind," it is more probable that Jean did not learn of the offer or there was miscommunication. Her French agent Olga Horstig-Primuz said Jean never turned down a film that later became a success. It is almost inconceivable she would not wish to be part of Day for Night considering some of the roles she did agree to during that period.
Jean's Airport co-star Jacqueline Bisset took the role earmarked for Jean, and the film won the Academy Award for Best Foreign Film and the BAFTA for Best Film.GM