Despite the rave reviews from the other fans on here, I feel compelled to speak some truth and even this out a bit from a more objective standpoint. While this is indeed the longest of the Fantomas films--or serials, really. While the first two films move at a fairly quick pace, the third plays as more of a mystery, with Fantomas rarely on the screen. This is especially a shame, as he now finally dons his Executioner hood, looking more diabolical than ever, yet he unfortunately has an estimated total of five minutes screen time with this new attire.
While the murder/mystery storyline is at first compelling and interesting, it quickly dissipates into a boring, convoluted mess. For starters, gone is Fantomas' disguise gimmick from the beginning of the first two serials. While not imperative, it served as an interesting look into the titular evildoer himself with some impressive effects, and as sort of a recap of the character himself. The most egregious aspect of the film isn't the story itself, but Feuillade's bland, static direction. Scenes go on for far two long, with the average shot length well over thirty seconds. While the camera blocking is at times well placed in its execution, each and every scene drags, testing the viewer to keep focused on characters or actions that matter, most of which are simply superfluous.
While the resolution is quite grisly in the motives and actions of Fantomas himself, the ending feels anti-climactic and rushed compared to the previous outings of suspense and mystery. While it's a necessary film to view in the series, be warned, for it's also the worst.