(at around 13 mins) When Fletcher returns to Nella Vago's window with a flower, he stands in the middle of a circle of smoked cigarettes he previously had discarded. However, when he throws the flower up through the window of her room (which is a long shot), he is standing outside the circle of cigarettes.
When Nella Vago is speaking with her teacher Rudwig, she sits on the couch, and he comes over to her. However, the orientation of his hands on the coach, as well as the way she is sitting on the couch, changes from one shot to the next immediate shot.
(at around 9 mins) A closeup of Fletcher's feet as he grinds out a cigarette butt shows 30 or more cigarette stubs strewn around his feet. A few minutes later when he returns with a flower and stands in the same spot, the number of cigarette butts is about the same, but many of them are in a different location or orientation on the cobblestones. Yet again, when Nella looks out the window after getting the flowers from Fletcher, the cigarette butts are concentrated in a smaller circle on a different set of cobblestones.