Erreur tragique
R: Louis Feuillade. B: Louis Feuillade. D: René Navarre, Suzanne Grandais, Ernest Bourbon. P: Société des Etablissements L. Gaumont, Fr 1913
Engl. intertitles

“There is an early ‘going to the movies’ episode, which develops some creative wrinkles on the use of film itself as a subject matter. The same year, the Thanhouser Company in the USA will release a nicely done mystery tale with a film industry background, The Evidence of the Film (Lawrence Marston, Edwin Thanhouser, 1913).
Feuillade will include an action sequence, about a horse and a carriage. This starts with the husband standing next to the horse – and looking oddly similar to the horse himself, in his tall boots. Humans and animals often ‘intergrade in appearance or behavior’ in Feuillade. Soon, there is a pair of Feuillade’s interesting camera movements, following a vehicle down a country road.
Erreur tragique includes one of Feuillade’s chateau facades, a building that comes complete with that Feuillade standard, giant gates with spiral metal work.
A bureau stands in one corner of the husband’s hotel room. It has an odd-looking, even surreal construction: one half is drawers, the other half a mirror. It is oddly like the double doors of rooms in other Feuillade. Like such ‘one door open, one closed’ constructions, the bureau is half one thing, half another.
The bureau also is at an angle in the corner, something that recurs in other Feuillade.
The husband at home is seen in a room, whose background walls are both at an angle from the plane of the screen. This seems atypical for Feuillade. Perhaps he is experimenting.”
Michael E. Grost

“In Erreur tragique, the film shown in the cinema resembles an actual film existing outside the realm of fiction. It seems to belong to the Onésime-series, a popular series that had been directed for Gaumont by Jean Durand since the summer of 1912. This series featured the actor Ernest Bourbon as the protagonist in films such as Onésime, l’amour vous appelle (Fr 1912), or Onésime, douanier (Fr 1913) and many others with similar titles. However, the film shown within Erreur tragique, ‘Onésime, vagabond’ does not actually belong to the series. It was faked by Feuillade, again using Bourbon as the main actor. For an audience familiar with the series, this was probably supposed to authenticate the fiction that the Count’s wife and her companion could really have accidentally blundered into the shooting of the film. Also important is that Bourbon’s acting style in ‘Onésime, vagabond’ is quite different from René Navarre’s (as the Count) in the main story of Erreur tragique. The Onésime film deploys the registers of the burlesque, intentionally exaggerating movements and gestures, and having the actors address the camera. Feuillade uses this as a contrast (‘cinema’ vs. ‘reality’) to the much more sober and almost anti-dramatic performance of Navarre, whom he had instructed to play in this manner, as the actor later confirmed.”
Guido Kirsten: Programmatic and Proto-Reflexive Realism: Feuillade’s La tare (1911) and Erreur tragique (1913)

Further reading:
Christian Quendler: Autopsy and Autography in the First Decades of Cinema