Video film shows various encounters by the Douro river, and fans are said to have bolted horns with the neighborhood police after the bars shut down at 10.30pm.
English Fans have been showing up in Porto over the last couple of days for the ultimate Champions League final on Saturday.
UCL Final: Chelsea and Man City fans clash with Porto police
There were no severe wounds sustained from the occurrence.
Manchester City face Chelsea in the Champions League finale in the Estadio do Dragao on Saturday.
Just 16,500 fans are permitted to watch the match in the arena, 33% of the 50,000 stadium limit.
One video clip showed a turbulent scene with various individuals stumbling into a street, horns booming, whistles and hollers upsetting the evening.