Vladimir Luxuria, a former Communist lawmaker in the Italian parliament who has become a prominent transgender rights crusader and television personality, was led away by four men while shouting "I have a ticket."
A few minutes later she was put in a car and driven away.
She had been walking around the Olympic Park for about two hours in a rainbow-colored outfit and a huge headdress. She had been shouting "Gay is OK" in English and Russian.
Luxuria earlier said she was detained on Sunday evening by police who told her she should not wear clothes with slogans supporting gay rights. Police denied detaining her.