The 43-year-old man had met a woman four years his senior in a bar in the southern German city on Monday and she took him back to her apartment for sex, a police spokesman said in a statement.
"There they had sexual intercourse several times," the spokesman said.
"When the 47-year-old wanted even more, her partner said no."
The man then tried to leave the apartment but the woman prevented him from escaping and demanded he have sex with her again.
"Because the 43-year-old saw no other alternative, he complied with the woman's wishes another few times so he could finally leave the apartment," the spokesman said.
"But when she continued to refuse and demanded even more sex from him, he fled to the balcony and alerted the police."
The woman "then tried to talk the dispatched officers into similar activity but was unsuccessful".
She is now facing possible charges of sexual assault and illegal restraint.