A Canadian researcher says it is indeed, in a silent film taken on November 14, 1904, when the author of "In Search of Lost Time" was 33 years old.
The man thought to be Proust appears in the 37th second of the clip, which lasts one minute, 11 seconds and was published Wednesday on the website of the French magazine Le Point.
Wearing a grey top coat and black bowler hat, he is leaving the high-society wedding of Armand de Guiche, a close friend of the author's, and Elaine Greffulhe, a great-niece of Robert de Montesquiou, who inspired the Baron de Charlus, one of the main characters of "In Search of Lost Time".
The seven-volume masterpiece, dwelling on the theme of involuntary memory, has also been translated with the title "Remembrance of Things Past".
Although several photos of Proust survive, "It would be the first discovery of a film with the writer," said Jean-Pierre Sirois-Trahan, a professor at Laval University in Quebec, who presented his findings in La Revue d'Etudes Proustiennes, a literary journal specialising in Proust.
Sirois-Trahan, a cinema specialist, combed through press reports of the high-profile wedding, which listed Proust as a guest, and then located the film at an archive near Paris.
Unlike nearly all the aristocrats attending the wedding, Proust is not wearing a black jacket nor the requisite top hat, and he quickly exits the church alone.
"It's possible to imagine that for Proust, this is his 'artistic' way of standing out," Sirois-Trahan suggested.