Detective Superintendent Petri Juvonen said the fight spread from a popular gay bar early Thursday into the street where Lambert was suspected of hitting two people who tried to break it up.
Juvonen said that Lambert's boyfriend, "Finnish Big Brother" star Sauli Koskinen, also was held for questioning. He said no weapons were used, no one was seriously hurt and that it was not "a very serious incident."
Police said the two men were released after a few hours and that no further action would be taken.