The Swedish man worked as a police officer in Sweden, but was not on duty when the assault took place on June 30 at Islands Brygge, the same evening that Sweden's match against France in the World Cup was to be shown on a big screen.
The 31-year-old man who was taken into custody on Wednesday is the only person arrested in the case.
According to Danish media, witnesses have said that several people were involved in the assault on the Swede. Copenhagen police cannot confirm the information, but say they are investigating whether more people were involved.
The suspect has been in custody since the beginning of July, suspected of the Danish equivalent of assault.
