This picture is famous, and I think justly. Begin with the impact, lost on us now but still striking in 1877, of showing that an urban street's story is worth telling on canvas. Then observe the fine draftsmanship and the skillful effects like the water on stone, qualities that never lose impact.
I am also struck that the most dramatic effect of perspective, the vanishing-point building, is tempered not just by being in the background but by the faded colors of distance. Caillebotte is not striving to impress, but is creating a balanced design.
The story itself, for me, focuses on two pairs of eyes. The eyes of the top-hatted man look across the street at something, or someone. Hers, it seems, look at him.