Two people were arrested following an incident on the Halftown Road area of Lisburn, which reportedly happened in the vicinity of a beer tent after the show finished on Thursday evening.
Officers were also called to another altercation on Friday night, which police say was not linked to the earlier incident.
PSNI Constable Richard Taylor said: “Enquiries are ongoing, however we would appeal for anyone who witnessed anything to come forward. If you can help, please call the 101 number. Alternatively, information about crime can be passed on anonymously via the independent Crimestoppers charity on 0800 555 111.”