The two men, both 21 years of age, were sitting in the row in front of the women in a cinema in the Tiergarten neighbourhood when the incident occurred, police report.
But instead of stubbing out their cigarettes, they turned around, hit the women in the face, ripped at their clothes and then threatened them with a knife.
The young men then fled from the cinema in a taxi. But the women were able to note down the taxi number, leading police to arrest the pair shortly afterwards.
The women were treated at the scene by medics.
In an unrelated incident, a man attacked a lesbian couple in the centre of Berlin on Sunday afternoon as they were sitting on a park bench.
The 30-year-old approached the women and started talking to them in English. When they told him they weren't interested in a conversation, he went away. But shortly later he returned and stood right in front of one of the pair, who pushed him away. He immediately reacted by kicking and punching her in the head.
When the women's 28-year-old girlfriend tried to defend her, the man threw a bottle at her head and began to strangle her. The woman fell to the floor and lost consciousness.
Bypassers who were alerted to the assault were able to restrain the man until police arrived.