I'm wondering how
Giovanni Boldini (1842-1931) painted these pictures of dynamic street life. I assume they're painted from observation and not from photos.
If I was tackling such a subject. I would rough in the composition on location. In another session I would have the model pose on a patio or sidewalk, then go back and finish up the background on the spot.
Same with this one. You could do it in sections. A groom could hold the harnessed horses in the same lighting as the background scene.
It's possible that this scene came readymade, but it's also possible he painted the house and trees of the river scene, and then grabbed the steamboats, rowboats, and ducks in other places and added them to the half finished painting.
I love the way Boldini is so playful and daring in his paint application. He appears to be using a variety of brushes: big ones, small ones, new ones, and old ones.

Sometimes students want their set of brushes to be all new and fresh, but experienced painters also cherish their worn, splayed brushes.
This painting of a riverside laundry appears to be a plein-air study.
This related work is also small (13 x 20 inches), but it might have been completed in the studio using plein air sketches as reference notes. I'm just guessing here, and if anyone knows more about this, please share in the comments.
If indeed Boldini composited elements in these paintings, he would have started with the idea in sketch stage, and then built the picture from elements he found. It's like what Ansel Adams said about camera work: "You don't take a photograph, you
make it."
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Book about the exhibit of Boldini's French Landscapes:
Giovanni Boldini in Impressionist Paris (Sterling & Francine Clark Art Institute)