。
She puts on makeup in public.
Literal
She [topic-は] in-public [at-で] makeup-does.
A simple sentence that carries cultural weight. Applying makeup in public spaces — particularly on trains — is widely considered poor manners (マナー違反) in Japan. The sentence doesn't explicitly pass judgment, but a Japanese reader would likely register this as describing socially frowned-upon behavior. 化粧する (けしょうする) is the standard verb for putting on makeup.