This is adapted from the Hans Christian Andersen story about a neglected, destitute matchbox girl who turns to light for a last flight of fancy. So how to transmute suffering into something that matters and we can take from?
It's so perfectly tailored for cinematic language of the time, sentimental but not daft; an outer story about hard-hitting emotional drama, ostensibly realistic but itself imbued with the afterglow of fairy-tales, and the canvas nested inside the mind that permits all manner of fantastic associations between the two fantasies.
The cruel father who sends her out to sell every night, is beautifully rendered as only a dark silhouette behind a window. Once out in the snowed street, the only one who notices the girl is the policeman. In their brief moment of intimacy before a shopping window they identify each other as toys behind the glass panel. It's good to note the distance they feel separates them, and therefore prohibits the romance, because it's repeated, then reversed inside the fantasy. They are again faraway, but eventually - imagined - very close.
The fantasy is brilliant, but first seems rather uninspired, the magic uncinematically transferred to the set design. But what seems at first as stuffy is revealed to be stuffy for a reason; the feeling is one of stasis and regression, the toys are life-like in size, so the girl reduced to their stature, hiding among them, finally finding love that extricates from the infantile level. Then a premonition of Death as the casting of the first shadow, here is where it soars and takes to the skies.
This second part truly amazes; Renoir does not merely transmute on the symbolic level by transferring notions between worlds, he transmutes for the eye as well. This heavenly world is in flux, rapid, violent. So we have a delirious flight of fancy as the couple flees from Death, a struggle, and eventually the capitulation.
You can read all of this as the wish-fulfillment of a suffering mind, the fluid dream world providing guidance from inside, or a spiritual blueprint with those things nested inside of it.
Eventually the cross, the rod of suffering, is transmuted in the tree of new life. We may think the blossoms spring up wistfully, because the fairy-tale calls for it, and perhaps for the filmmakers they were merely the proper symbols, but it is not quite so. Fairy-tales communicate something of our very soul, not the opposite. A common soul on her journeys through the world.
So, on an unconscious level, a sacrifice here points the road to the required breakthrough. The girl growing into a woman, then growing out of that too, and is a river its bank or the flowing water? Watch it again.