This film from 1954 is surprisingly modern and still unusual in the way it tells the story.

A miniature world in the backyard
The world in the movie is confined to a courtyard in the back of the surrounding block. We get a glimpse of the rest of the world through a small alleyway that leads to the "outside world". We see cars and people pass by, while the main plot happens in this self-contained little world.

Besides a few shots where we're seeing what happens in our protagonist's apartment, most of what we see is from his point of view: The rear window of his apartment.
There are a bunch of other people we can see going about their lives - and each of them comes with their own oddities. The dancer, the pianist, the couple who's lowering their little dog in a basket, the caged bird(s?) on the window sill and of course the couple that spends the searing-hot nights on the stairs outside of their apartment, moving the mattress, pillows and all each evening and morning.
Voyeurism and patriarchy
The film is definitely showing that it's a work of its time. There is the "nagging wife" trope, for example. But the general theme of voyeurism - our protagonist is bound to a wheelchair after an accident and decides to get his entertainment from spying at his neighbours as they live their lifes in front of his window - is timeless. We're forced to join in as his eyes wander over the young female dancer, the married couple going through some disagreements and all facettes of life as it unfolds.

Light, shadow and psychology
What particularly caught my eye is how well light and shadow are used.

Our protagonist often sits in his own apartment in dimmed light. Showing us that he's isolated and focuses attention outward, rather than living his own life.
Then there's the antagonist - a potential murderer after all! Most of the time they're lit within their bright apartment. They're focused on their own affairs - until they connect with our protagonist.

Suddenly he's also dimly lit - focusing his eyes on something in our direction. The light focuses entirely on his gaze. His glasses reflecting a single point of light - is that coming from us? Have we been found out?
Our protagonist is basically powerless - he has to visit, like staring onto a staged play, whatever happens.

Often times we're only hearing something or seeing the reflection or reaction from our protagonist, rather than seeing the action directly.
The Camera
I also love that we're seeing an up-close shot of the Ihagee Exacta VX - a gorgeous piece of technology from Dresden.
I may, to the dismay of my wife, have paused the movie when I thought I spotted "Dresden" on the front plate. Worth it, tho.
A wild ride
The whole film is a wild ride. We're thrown into the life of this successful photographer, bound to be a spectator and stuck in his apartment during a sweltering heat wave.
We get caught in his voyeurism - the male gaze resting on his younger neighbour. This serves no other purpose than an uncomfortable male gaze. And then we all, the protagonist, the people he's seeing and we, the audience, get bound together in the curiosity to find out if a neighbour became a murderer or not.
Gripping, wild story, told through the eyes, camera and binoculars of our protagonist.