You can certainly find exhaustive commentary on this film elsewhere, if you please.
We're here for the faces. Finest among them: the startlingly modern Louise Brooks:
I prefer her already-worldly version, as in "Pandora's Box," but the virginal good-girl role fits her well. Basic story: Seduced and abandoned, she ends up in a home for the wayward - which of course run by all sorts of creepy archetypes. Beware of bald tall Germans running an all-girl boarding house:
What really makes her Lost is the path to perdition she follows after she gets out. She not only becomes a prostitute, she learns to drink. In this scene, the clientele and the other working girls have surrounded her to urge her to drink. Drink! Drink! Join us in blurry happy funtime Weimar hell! The scene shows something a few modern filmmakers might profit from understanding: the superfluity of dialogue.
We wandered in from a comedy they're shooting next door; mind if we help with this scene?
Drink, honey! It's great! Helps me pretend I'm with an actual woman:
Bottoms up, dear; Grandma insists.
And so she drinks.
Once under the spell of Demon Beer, she takes up with a client . . .
. . . and it's here we get the unsettling feeling that the friendly madam - that's her in the foreground above - might not have the Lost Girl's interests at heart after all:
It's melodrama, sure, but Brooks is luminscent throughout, complete with that famously Modern Hair.
Speaking of modern hair: the movie contains a comic scene with an exercize instructor, and you get an idea how they saw the "physical culture" types in 20s-era Germany: wierdos who probably smelled like a goat.
To remind you that the world did have color, here's the original poster.