‘It is a song that resembles us’ (‘C’est une chanson qui nous ressemble’) is a well-known line from the classic love song Les feuilles mortes, written by Jacques Prévert and composed by Joseph Kosma in 1949. It was made internationally famous when performed in French by Yves Montand and then Juliette Gréco, and also became a hit in English – both Frank Sinatra and Nat King Cole made it their own. It belongs to a large repertoire of popular chansons that most French people recognise instinctively as part of their cultural equipment – a song that resembles them.

In the popular French television series Dark Hearts (Coeurs Noirs) – about a French special forces squad operating in Iraq in the run-up to the Battle of Mosul in 2016 – the chanson makes an unexpected appearance. A group of French soldiers, accompanied by Salar, a Kurdish Iraqi who acts as intermediary and interpreter, are driving in two different jeeps on their way to what they know will be a dangerous operation. Over the course of previous episodes, the viewers have become familiar with the drama’s characters and with the enormously pressured circumstances, both military and personal, in which they operate. Other members of the group have suffered catastrophic injuries; some have been killed in action; some characters are at breaking point in their private lives. Then Sabine, the team’s female elite sniper, who is driving one of the cars, notices that Salar, in the passenger seat with his eyes closed, is listening to a song with an earpiece – quite likely as a way to settle himself in preparation for a violent encounter with the enemy. When asked what he is listening to, he responds, with slight embarrassment, that it is only ‘an old French song’. Sabine persuades Salar to play the song on the car stereo and as he does so, she and the other soldiers in the car immediately recognise it – Elle est d’ailleurs (‘She is From Elsewhere’) by Pierre Bachelet, a romantic ballad that was a hit in 1980. Sabine relays it to the group riding in the other jeep on her walkie-talkie so that the whole team may listen, and they all sing along together.

The strength of the scene comes from the effect of surprise: Bachelet’s gentle song breaks into a scene of war and violence with an otherworldly efflorescence of amour courtois, its lyrics full of reverence for an adored woman whose beauty is evocative of Venice, of lacemaking, of a painting by Vermeer. This is made more significant by the presence among the team of Sabine, a female soldier whose arrival at the base has caused unease among some of her male colleagues because their instinctive need to protect her makes them more acutely aware of the danger they are all facing. Then there is the characters’ nuanced response in the face of a song which is neither a martial chant nor a pub anthem to be belted out collectively. As Bachelet’s voice travels over them like a wave it evinces among the various characters recognition, delight – at finding that various fragments of the lyrics can be summoned to memory – and amusement, because the old French song’s gentleness, sincerity and romanticism prevent it from being entirely cool.

When he came up with the idea of featuring Elle est d’ailleurs in the scene, Ziad Doueiri, the French-Lebanese director of Dark Hearts, encountered some scepticism: surely the song was too old-fashioned; it wouldn’t work. But, drawing on his experience of 1970s Lebanon, where many French stars, from Charles Aznavour to Dalida, had given memorable performances, Doueiri was adamant that this was the right song to pick out. It would elicit a moment of fraternal communion, galvanising the team and bringing them together while also helping the soldiers to perform, more or less consciously, an act of remembrance for the peaceful world they had left behind.

The result is indeed very moving, in part because, as the soldiers sing along together, the tension of the military expedition dissolves, replaced with a poignant carefree holiday mood, and accompanied by a powerful burst of nostalgia – individual memories of childhood and school come flooding in. But crucially, the experience is collective. The song belongs to them all: it is a part of the cultural baggage the French team have in common with each other, and the character of Salar, who is Francophone, shares it too.

What gives songs like Elle est d’ailleurs, Les Feuilles mortes, La vie en rose by Edith Piaf, Ne me quitte pas by Jacques Brel and so many others their enduring power? In the tradition of French chanson, the lyrics of popular songs aspire to the status of literature and will often attempt to tell a story, to evoke an emotional landscape ranging from despair and sardonic existentialism, as expressed by such prestigious artists as Barbara and Léo Ferré, to the plangent longing and melancholy of Françoise Hardy or the joyful exuberance of France Gall. Those lyrics, along with fables of La Fontaine memorised at school, and with memorable lines of dialogue from favourite films, become absorbed over time into the conscious and unconscious memory of large numbers of people who do not know each other, but are nonetheless intimately linked by their knowledge of the Francophone songbook.

It is characteristic of this tradition, in which chanson is aligned with other high arts, that a maker of poppy dance hits like the French-Canadian star Mylène Farmer should, in many of her songs, include references to the poetry of Charles Baudelaire, to François-René de Chateaubriand’s Mémoires d’outre-tombe (‘Memoirs From Beyond The Grave’), to the novels of Virginia Woolf or the paintings of Egon Schiele. She also enjoys hinting at hidden subtexts in her songs and in sophisticated music videos. Thus the video for Sans contrefaçon (Without Counterfeit) a 1987 pop song about a girl who enjoys cross-dressing as a boy, is a marvellously unsettling short film about an itinerant ventriloquist and his dummy (an avatar for Farmer herself). The latter, bewitched by a sinister circus performer, comes to life, like Galatea (and Pinocchio), just long enough for the ventriloquist to fall in love with her, before returning to her wooden, inanimate state.

There is a profound affinity between French songs and French films – their quotable quality and their Proustian ability to capture and later restore an emotion. This powerful ability to trigger memories was harnessed to great effect in the work of film director Jacques Demy, who, in films like Les parapluies de Cherbourg (The Umbrellas of Cherbourg, 1964) and Les Demoiselles de Rochefort (The Young Girls of Rochefort, 1967) managed the unusual feat of adapting the Hollywood musical, in particular the dazzling MGM films of Vincente Minelli, such as An American in Paris (1951) and The Band Wagon (1953), to French-language cinema and to a French sensibility. Like Minelli, but in the context of his own French Nantais provincial origins, Demy created in his films a constructed artificial world whose enchanting otherworldly quality arises from an expressive use of colour (ravishing pastel colours are often matched with a tragic storyline in Demy’s universe) and from the way his stories and characters are largely expressed through music and song.

Demy was experimental in his approach: in some of his films the whole of the dialogue is sung along to the score. He was a travelling companion of the Nouvelle Vague and was married to the equally innovative Agnès Varda. He thrived in a French postwar context of fascination for the vividness of American culture conjoined with a fierce attachment to French-language songs. And it did Demy no disservice that several of his films – Les parapluies de Cherbourg and Les demoiselles de Rochefort but also the fairytale Peau d’âne (Donkey Skin) have Catherine Deneuve as their star and figurehead. Especially important was his enduring collaboration with the composer Michel Legrand, the author of Demy’s film scores. Together they invented musical comedy à la française on the strength of songs that became embedded into the French psyche, the Chanson des jumelles (The Twins’ Song) for example, or the Conseils de la Fée des Lilas (The Lilac Fairy’s Advice). Demy brought to musical comedy a radiant pessimism highly sympathetic to the French sensibility.

One notable heir to Demy’s chanson-inflected cinema is François Ozon, who in Huit femmes (Eight women, 2002), delivered a whodunnit and musical comedy with an all-female cast of French stars that includes Danielle Darrieux, Catherine Deneuve, Isabelle Huppert, Fanny Ardant and Emmanuelle Béart. Ozon, who like Demy is a lover of artificiality and constructed worlds, reveres the melodramas of Douglas Sirk and Rainer Werner Fassbinder. He adapted a 1958 stage play by Robert Thomas and enriched it with musical numbers in which the actresses take turns to perform a cover of a well-known French song. There is rich comedy in seeing some of the divas of the French screen perform familiar pop songs, and the tunes are often used ironically, since Ozon delights in skewering the hypocrisies and perversions of the bourgeoisie. But there are also poignant moments, such as when unloved spinster Augustine (Isabelle Huppert) sings Message Personnel, a song by Françoise Hardy which encapsulates all the painful yearning of unrequited love.

But the greatest example of a deliberate and intensely knowing use of the French songbook in film in order to provide a communal experience for the audience remains Alain Resnais’s fascinating film On connaît la chanson (Same Old Song, 1997). This is a comedy of manners saturated with melancholy and (comically) peopled with depressive characters, interconnected bourgeois Parisians wrestling variously with hypochondria, infidelity, depression, medieval history, unrequited love and the complexities of the city’s property market. An assumption that melancholy is the glue that binds people together – French people at any rate – appeals to the French. That French songs should be a vehicle for this is typical of how the French like to imagine themselves. The title of the film is a French expression meaning, with a mixture of lassitude and impatience, that one has heard it all before. It also means, literally, that here is a song that we know, and as the film contains snippets of very familiar songs which the actors lip sync to, the title also comes to suggest the joy of recognition, of finding, like the French soldiers in Dark Hearts listening to Elle est d’ailleurs, that you do remember the words to the song that is playing, and that the song is in some ways a part of you.

In that moment – during the few minutes carved out by a song or a song fragment – we know exactly what’s coming, we know the lyrics by heart, and this marks a temporary bridging of the isolation between separate individuals, a suspension of existential loneliness. When, in On connaît la chanson, a character begins in the midst of dialogue to mime along to a snippet from a popular French song, it is as though the medium of chanson is used to disrupt and re-enchant the ordinariness of everyday life and its tiresome repetitiveness. The fragments of song allow the characters in the film to sing their lives, to express their experience differently. That is also, of course, what songs can help us do in real life, and there is a special pleasure in seeing it happen on screen. The film appealed to large audiences. For Alain Resnais – a resolutely experimental filmmaker and among other things the auteur of Last Year in Marienbad – On connaît la chanson was his greatest commercial success.

In On connaît la chanson, Resnais is preoccupied with how deceptive appearances can be and his way of exploring this (which is also a tribute to Dennis Potter’s The Singing Detective and its surreal musical numbers) is to have his characters break into song at moments of crisis, revealing their true feelings and motivations. It sometimes seems as though the unconscious is singing. This is particularly effective in view of the rich variety of songs featured in the film, from Maurice Chevalier’s Dans la vie faut pas s’en faire to Alain Bashung’s Vertige de l’amour, from Josephine Baker’s J’ai deux amours to Serge Gainsbourg’s Je suis venu te dire que je m’en vais. Spanning the period from the 1930s to contemporary pop, the overall effect is kaleidoscopic.

In selecting songs for the film, preference was given to rengaines, very well-known songs whose chorus everybody would know because the tune and the lyrics, heard countless times before, would have seeped into collective consciousness. Such songs, absorbed for the main part passively, through exposure to the cultural mainstream, remain present subliminally and when summoned, appear – like ghosts – and return the French to a whole forgotten continent of shared memory.

But what about non-French lovers of French chanson? Why do people the world over enjoy listening to songs sung in French? Salar’s character in Dark Hearts in one such person. In the context of Dark Hearts there is the intimation that French is one of the languages spoken by many in the Middle East and which creates a bond between those who speak it, wherever they are from. Beyond this, and even when a song’s lyrics remain unintelligible or are only understood in part, through French chanson a certain idea of France is shared, projected and experienced. Hearing Les Feuilles mortes performed by Juliette Gréco, for example, would in the early 1950s have allowed anyone, wherever they were in the world, to close their eyes and imagine themselves transported to Paris, perhaps sitting in a café in Saint-Germain des Prés, or striding down the Champs-Elysées. The song still operates in this way today. Even when you don’t know French you might know that this is a French song, and that is an invitation to share in a common fund of imaginary references.

The influence of French language and culture lives on in contemporary chanson, which, in the songs of artists such as Zaho de Sagazan, Clara Luciani, Keren Ann, Mika and Victorien, remains rooted in a lyrical, literate tradition. Despite the success of American and British artists in France, the French save a large part of their cultural and emotional allegiance for the French songbook. And like the soldiers of Dark Hearts, they sometimes find great solace in plucking a song from their secular hymnal.