Monet painted from a low vantage point, looking up at Camille. His child is further back, around eye-level. This creates an interesting play in terms of perspective and space. The low vantage point also gives dominance to the sky.
In terms of focal points, my eyes are drawn towards Camille’s face first, then the child’s face, even though they are both simplified. That’s the power of facial features. We are programmed to look for them.
With that being said, the two figures are fairly balanced against the dramatic surrounding nature. It’s an unusual painting in this sense: it’s not a pure portrait, and it’s not a pure landscape. It’s a hybrid of both. If the woman and child were farther in the distance, it would be a landscape. The Poppy Field comes to mind. If Camille were closer and more rendered, it would be a portrait.