Paranormal Activity originally came into New Zealand with an unrestricted rating of 'M' and the descriptive note 'contains offensive language'. It had received its rating through the cross-rating process based on the M-rating it had been given in Australia.
Find out more about the cross-rating process
After complaints from members of the public, the Chief Censor called the film in to be classified by the New Zealand Office of Film and Literature Classification. As a result, the film was classified as 'R16: contains horror scenes and offensive language'. This classification also applies to the DVD version of the film.
Micah and Katie, a couple living in a suburban house, become increasingly disturbed by a demonic presence in their home. Micah, a sceptic, decides to
run a video camera to capture the demon’s activity whilst they sleep. The activity becomes more frequent and aggressive, and Katie’s nocturnal behaviour begins to change.
The film is shot entirely by hand-held camera, and the film is presented as being made of 'found footage' – all footage seen appears to be shot by Micah or Katie.
In countries around the world there were reports of people collapsing at cinemas from fear either during or after watching the film.
Read an article from stuff.co.nz about the film being 'too scary for Italians'
Members of the public complained to the Classification Office about Paranormal Activity's unrestricted rating. They felt that the film was very frightening and contained extremely disturbing themes. One complainant said that her 13-year-old son was extremely disturbed after watching the film.
Under section 13 of the Films, Videos, and Publications Classification Act, the Chief Censor can decide to classify a publication that hasn't previously been seen by the Classification Office, such as a cross-rated film. A copy of the film was sent to the Classification Office to be examined and classified using the criteria set out in section 3 of the Classification Act. 
There is not a lot of blood or violence in this film. Instead, the film-makers use simple but effective techniques to build the sense of fear and tension as the film progresses. A lot of the 'horrific' action happens off screen – the audience experiences what is going on by hearing it and by seeing the characters' reactions.
After viewing the film and applying the classification criteria, an R16 classification was assigned to the film. In the summary of reasons for the decision, the Classification Office noted that:
The images of horror, the sinister supernatural themes, and the tension and realistic fear the characters experience in the film are likely to be greatly shocking and disturbing to younger teenagers and children.
Although deliberately designed to scare and disturb all viewers, adults and older teenagers will be more likely to be able to put the images and themes of the film into context. Children and young teenagers, on the other hand, are likely to sustain lasting damage from seeing films like this, including nightmares and persistent upsetting thoughts. Therefore, the film is restricted to persons who have attained the age of 16 years.
Check out our Horror genre case study