For a good chunk of his output in 1899, Georges Méliès committed himself to creating a series of short films detailing the events of the Dreyfus Affair political scandal, which was still progressing in France as the series was made. The serial, centering around Capt. Alfred Dreyfus who was accused of writing treasonous letters and discharged as a result, flared up the public which had already been divided into two groups: the Dreyfusards and the Anti-Dreyfusards (Méliès was one of the former). In the end, censorship was the answer--theater owners couldn't handle the disputes that the serial caused during showings. Thus, "The Dreyfus Affair" is now considered the first censored political movie.
Episode seven in the eleven-part serial takes place at the prison in Rennes, where Dreyfus was taken to await a second trial after Colonel Henry's suicide. He's shown to be studying law books with defense attorney Fernand Labori (portrayed by Méliès himself, in doing so obviously stating his side in the matter) and Edgar Demange. Soon, the prison guard announces that his wife is here, and Dreyfus is all too happy to be reunited.
Again, this film doesn't play a big part in the serial as a whole, except showing the interior of the defendant's new prison. I doubt if the action of this film is a true event in history, so it's fair to say this gave Méliès a good excuse to show off a nice set, play a part for an extra episode, and continue to gain sympathy for his beliefs. Another reason may have been that it was probably a good way of introducing some new characters into the serial.