“Would we say Miyazaki is a fairytale director?” asks Sciamma. “Yes,we would,but that would be the beginning of the conversation,right? I think it’s a celebration of how cinema is a kind of fairytale,but it’s not written as one.”

There is,of course,an underpinning of the uncanny to this strange meeting,but its subject was the real relationship between a child and parent. “The thing I had in mind the whole time I was writing the film was what kind of impact I wanted it to have on a mother and a daughter watching it together,” says Sciamma. “Watching the film and then when they get out,they have to run to get the bus – and they will run differently,together.”

It wasn’t until she was well into writing it,says Sciamma,that it struck her thatPetite Maman was also a time travel story,with all the ethical questions that raises about whether a time traveller can fix the future by changing the past. “And I realised I would have to deal with that. I mean,I love time-travelling films! I am part of theBack to the Future generation.”

But she wanted to avoid anything to do with time machines – the cinema is its own time machine here – or teleporting characters between heavily set-dressed historical epochs. That felt too thematically heavy,too far from real life. “If you ask people what would you do if you had a time machine,they will say ‘I’d go back to Egypt to see Cleopatra’ or ‘I would go back and kill that guy’,” she says. “It’s never ‘I would go back and share a bike ride with my grandmother during World War II’. But why? Why wouldn’t we use time travel with a very intimate objective? So that’s what I wanted to do.”

It is a personal film in that it is an idea that has nagged at her. “I really feel you are travelling in my brain,” laughed Sciamma when she first presented the film at the Berlin Film Festival. It is not her story,however. The point of asking what could happen if children could meet their parents on equal terms was not to deliver an answer,but to allow viewers to graft their own experiences on to the narrative. “That’s also why it’s so short. It’s not building a lot on that situation;it is trying not to exhaust it too much. It’s not this idea that belongs to me or the film or even to the characters. It’s more alive than that.”

Sciamma’s breakthrough film,Tomboy (2011),centred on a child of 10;her next film wasGirlhood (2014);she also wrote the script for the much-awarded animated filmMy Life as a Zucchini (2016).

“I don’t feel like I have this special connection to childhood,” she says. “I am just being honest,I think,radically honest about the fact that children are clever,committed,sensitive human beings going through the same crises,especially these days,as all of us.”

With every actor,she says,she sets out to create a collaboration. It makes no difference if they’re eight years old. “I am taking them very,very seriously – which is something I always do with characters.”

Petite Maman doesn’t fit anyone’s mould,but has been received rapturously everywhere it has shown. Clearly,it’s a bedtime story we want to be told.

Petite Maman opens on May 5,with previews this weekend.

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