Four stars.

One fine day, did Mia Hansen-Love wake up with the idea of casting James Bond's love interest in the last two 007 movies, Lea Seydoux, as the lead character of her new film? We may never know how it really came to pass, or whether the filmmaker considered this glamorous casting risky, but it turns out to be an opportunity for the French actress to show, in a nuanced and engaging performance, how good she is.

This latest film from Hansen-Love is of a piece with the thoughtful and subtle films she has made and impressed us with. The French writer-director has been steadily developing a distinctive profile as a filmmaker of work like Things to Come, Father of My Children and Bergman Island. Her small-scale human dramas with a delicate, naturalistic aesthetic are searingly intimate, and not a bit glamorous. It is not surprising to discover that she is the daughter of philosopher professors.

The main character here, Sandra (Seydoux), is also, as it happens, the daughter of a philosopher professor, Georg (Pascal Greggory). One imagines a childhood in spaces lined with books, and indeed where to place his vast library once he succumbs to a degenerative neurological disease becomes an issue for her and the rest of the family.

Although Sandra visits him in care frequently and is concerned for his welfare, her father has stopped recognising her. Perhaps more than her sibling and mother, Sandra reflects on the clarity and rigour that once obsessed her father that have now all but completely disappeared.

As he has been divorced for many years, it is time to find a permanent place for him in institutional aged care. His former wife, Sandra's mother Francoise, is a feisty feminist and environmentalist played with edgy good humour by Nicole Garcia.

The difficult process of finding the right aged-care facility is not entirely Sandra's responsibility, though she does appear the most engaged, feeling her father's decline the most intensely. Her sister Elodie (Sarah le Picard) and her husband and family are also in Paris. Francoise is there too, throwing in her lot with the youthful extinction rebellion activists on the streets. Her relationship with her ex has not been unfriendly, but there is a new partner for Georg, Leila (Fejria Deliba), who is also on the scene.

The scenes between Sandra and Georg here recall a batch of recent films wherein a child has to cope with an ageing parent suffering with dementia and other age-based diseases. The Father with Anthony Hopkins and Olivia Colman and Still Alice with Julianne Moore and Kirsten Stewart come to mind.

Seydoux brings a particular delicacy to her role as Sandra the grieving daughter, in another demonstration of the range that we have already seen in her roles in auteurist and mainstream cinema. Her hair is cropped gamin short, a style reminiscent of Jean Seberg in Godard's iconic Breathless, but there is nothing flaky about Sandra, a linguist who works as an interpreter, translating at conferences and events.

At home, she has a spirited eight-year-old daughter, Linn (Camille Leban Martins), for whom she has had sole responsibility since she became a widow. The relationship between the two of them has a lovely natural quality, like so many of the relationships here.

Into this thicket of robust emotions, wanders Clement (Melvil Poupaud), a friend of Sandra's late husband. He and Sandra run across each other and there is an instant attraction. He is a cosmo-chemist, not the astrophysicist that Sandra keeps mistaking him for, another professional who also works in an exacting space. Modern life is demanding for everyone, but further complexity is quickly established when Sandra and Clement begin an affair. Clement is married with a young son.

While Sandra is constantly in demand on her round of responsibilities and the complications mount, the likelihood of waking to a bright clear day seems to be receding ever more quickly. One Fine Morning is about letting go and about a reawakening of love and desire, a balance that Hansen-Love manages beautifully.