Writer and director of the film, Sara Summa, also stars in the film as Diana, alongside her real-life brother (for that little authentic cherry on the top) Robin Summa who plays the role of Arthur. The siblings are also joined by Diana’s two-year-old son Lupo (portrayed by Sara’s real-life child too) as they travel to Paris from Berlin in order to renew the MOT certificate of their late father’s old and very banged-up van which they now share, while attempting to mend some bridges, reminiscing about the good times (if there were any of course) as well as visit their mother on the route.

From the opening scene: a seemingly never-ending traffic jam has curtailed the journey for the siblings for now, and as expected, they engage in their first argument of the film, one that is clearly the latest of thousands they have shared during their life. The relationships between brothers and sisters are interestingly far more unique than others. No matter how old they become, there’s always the chance of it devolving back into a manner of childhood squabbles, but that’s the beauty of having a sibling: Will the rivalry ever actually end? Do you truly grow up in this way? Big questions that are difficult to answer, although Arthur & Diana offers its best version of a reply of sorts.

There’s some unfinished business left between the siblings though, which, of course, is the cause of said arguments. Diana is an academic; strong-willed and very opinionated and hot-headed. She still acts like the cliché big sister after all these years by controlling her brother and annoying him in a way that only big sisters know how to do. Her life is uninspiring though, and without her partner and child by her side, Diana would “set fire to it all.” Arthur is the calmer of the two (although bursts of anger will often be seen) and far more aloof but struggles somewhat to find his way in the world. He laments his sister for “abandoning” him some years earlier while he was in the care of their sick father, something he hasn’t and won’t be forgetting anytime soon.

Arthur & Diana bridges the barrier between documentary and fiction incredibly well by weaving real-life footage into its scenes to great effect. There are some wonderful segments of establishing footage that captures normal people living normal lives in Paris. By throwing this in, it offers a brilliant contrast to the film’s fictional narrative, but by combining it with the genuine conversations that the siblings have with one another, a beautiful and harmonious chemistry happens between the two. The technique is an extremely subtle one, but one that will intrigue even the fussiest of palates.

The film is a simple and sombre one that projects a truly authentic relationship between brother and sister, but even with a premise as simple as this, the execution is one that often comes across as messy and full of holes. The narrative does become slightly hard to follow at times, would you believe? It’s difficult to understand where the story is going, and your engagement might be tested along the way. As well as trying to attain a pass on the van’s MOT, and then visiting their mother (something that became an extremely brief affair), the siblings also visit a mystery party out of the blue but with no introduction as to what this party is and who any of the people are. There’s also a family dinner followed by a funeral, although whose funeral it is, is another mystery in itself. And then finally, there is the strange ‘Golden Owl’ subplot that comes in and out, before just being resolved in the blink of an eye – it’s overcomplications like this that can really undermine the hard work that the majority of the film had already achieved.

Arthur & Diana really is a lovely little film though, and one that really hits the nail on the head in regard to a truly authentic representation of the relationship between a brother and a sister. It just premiered at the 48th Toronto International Film Festival. About 70% of the Festival’s programme comes from independent and/or international producers.