Detectives are appealing for witnesses following reports of an assault which happened on Mevagissey Quay in St Austell on June 25.
The alleged incident happened between 9pm and 10pm where two victims, a man and a woman, were assaulted and punched causing injury.
A 20-year-old man from St Austell has been arrested on suspicion of assault and has been released on police bail until October.
Police have asked anyone who witnessed anything or can help assist police with their enquiries, to contact them by calling 101 or Crimestoppers quoting the relevant crime number 50230178475.