Is this the great French novelist Marcel Proust, captured on film in 1904?

A Canadian university professor claims to have found the only existing moving picture of French writer Marcel Proust.
The black-and-white footage of a wedding cortege filmed in 1904 shows a brief glimpse of a man in his 30s with a neat moustache, wearing a bowler hat and pearl-grey formal suit, hurriedly descending a flight of stairs on his own. Most of the other guests are in couples.
Jean-Pierre Sirois-Trahan, a professor at the Laval University in Quebec, believes the film, which he found in the Centre National du Cinéma in Paris, could contain the only known footage of the author.
Sirois-Trahan says the film is of the marriage of Élaine Greffulhe, daughter of the Countess of Greffulhe, who was one of Proust’s close friends and the principal inspiration for his character Oriane de Guermantes in À La Recherche du Temps Perdu (In Search of Lost Time).
Luc Fraisse, director of the Review of Proustian Studies, has no doubt the film shows Proust.