On practically every website and print article written on Jean Seberg, there have been errors in the number of films in which she appeared. In working with scholars as well as her family, the number stands at 37: 34 full-length features, two shorts, and one documentary which was produced while she still living. Post-death projects are not counted.
The full list can be found on this blogsite.
One error is the short film le grand escroc  and The Beautiful Swindlers. Le grand escroc was directed by Jean-Luc Godard as a continuation of Jean's Breathless character who, four years later, is a TV reporter for a San Francisco station and is in Morocco investigating a story.
Le grand escroc was to be included with other short films under the title Les plus belles esroqueries de monde (The Greatest Swindles in the World also known as The Beautiful Swindlers) but it was cut for various reasons depending on the source. Some claimed it was too weak a film, others reported the running time of all the shorts together was too long.
In John Kreidl's book Jean-Luc Godard (Twayne Publishers, 1980), Kreidl writes le grand escroc is the "clearest intellectually self-defining film Godard ever made... method and sentiment perfectly fuse. In all his other films, they are at loggerheads."
The short was later shown on television and a few international festivals. The second short Jean appeared in was her own Ballad for the Kid.
Not a traditional film actress, Jean was in Les hautes solitudes, a silent, black and white "experimental" film directed by Philippe Garrel of which is correctly listed in most of her filmographies.
A second film by Garrel entitled Les bleu des origines (The Blue of the Beginning)  that has been listed is arguable. Jean allowed Garrel use of her apartment for filming; however, she is not recognizable in any of the scenes (which would at least count as a cameo appearance and inclusion in her filmography) and is not listed in the film credits as being a performer in it.
Nevertheless, she did help Garrel with the use of her apartment, if not her name and talent.
La légion saute sur Kolwezi (The Legion Parachutes into Kolwezi also known as Operation Leopard) was the film Jean was working on at the time of her death. She had scenes filmed in Africa and returned to Paris for additional work in September. After her death, the scenes were reshot with actress Mimsy Farmer and Jean's performance on the film were not destroyed, but locked away without the public ever viewing the footage.
Since Jean does not appear in the finished film (as arranged by producer Georges de Beauregard and director Raoul Coutard), her last work is not considered. That distinction would be Die Wildente (The Wild Duck) which had its American release in 1977.
The one documentary film listed is the little-known work The Girls filmed in 1968. The work was intended to be part of a series and was directed by John Crome. According to Crome, the production company folded before distribution.
In The Girls, Jean talks about making films in Europe and comparing them with the Hollywood method. Other leading names including Joseph Janni (who was included because Julie Christie was unavailable) and Jane Fonda. Crome noted Jean was a bigger name than Fonda at the time.
Of the 34 feature films Jean appeared in a majority were American and French productions. But there were also British, Italian, Spanish, and German ones, and a range of genres and techniques which added to the uniqueness of her resume. There were comedies and dramas, "old" and "new" directors, writers and actors.
From silents to musicals, experimentals to standards, westerns to thrillers, love stories to suspense, and at times crossing one into another. Although Jean had hoped for another groundbreaking film like Breathless, she knew she was fortunate to have had that experience.
Most actors do not even have that.