Image caption Barbara was a French singer of Jewish descent who wrote Goettingen about a German city she loved

The post-war reconciliation between France and Germany was enshrined in a treaty signed 50 years ago. But many believe a song recorded the following year did as much to thaw relations.

Can there be many songs that really did change the world?

There have certainly been records which have been immensely popular - and some of those have had a message. But did they really change the hearts and minds of ordinary people? Did they alter politics?

There is one which did, and it's barely known now.

Fifty years ago, Germany and France were neighbours where the scars of war were still raw.

Germany had invaded France and been repulsed, inch by bloody inch and town by town. Germans were trying to come to terms not just with total defeat, but with how what they thought was their civilised country had perpetrated one of the great crimes of history.

Barbara, the woman in black Born Monique Serf in Paris in 1930

the second child of a Jewish fur salesman

family had to move several times during the German occupation and even fled one home after being denounced as Jews

studied music in Paris and then moved to Brussels, where she first performed under the name of her maternal grandmother

found considerable success in the 1960s and 70s

always dressed in black on stage

acted, directed and campaigned about HIV

death in 1997 sparked outpouring of grief

Into this minefield of potential resentment and painful rancour, stepped a slight, soft-voiced chanteuse.

Barbara was her stage name - she had been born Monique Serf in Paris in 1930. She was Jewish and so a target for the Nazis. But, two decades after the end of the war, she travelled to the German city Goettingen, as near to the heart of Germany as you can get.

She fell in love with the city and its people and recorded a paean of praise, first in French and then in German, the language of the former oppressor. She sang of "Herman, Peter, Helga et Hans". Who had they been, the listener wonders. Her friends? Her lovers?

It captured the hearts of her German audience at the Goettingen theatre. It became a hit.

A street was named after her. The city bestowed its Medal of Honour on her. The citation talks of the song and its "quiet, emphatic plea for understanding". The song's popularity, the citation says, "made an important contribution to Franco-German reconciliation".

As the song says:

"Of course, we have la Seine

And our Vincennes' wood,

But God, the roses are beautiful

Media playback is unsupported on your device Media caption Listen to Goettingen by Barbara

In Goettingen, in Goettingen."

And then:

"But children are the same,

In Paris or in Goettingen.

May the time of blood and hatred

Never come back

Because there are people I love

In Goettingen, in Goettingen".

One of the people in the audience was a student by the name of Gerhard Schroeder.

What leaders said about her Chancellor Gerhard Schroeder (above) - "[song] went to our hearts"

President Jacques Chirac - ''she was talent, intensity, stage presence, passion"

Prime Minister Lionel Jospin - ''a woman who knew suffering and understood the suffering of others''

He would later become Chancellor of Germany and use the words of the ballad in a speech marking the 40th anniversary of the Elysee Treaty of reconciliation between France and Germany, a speech made exactly 10 years ago.

He said: "I was a doctoral student in Goettingen when she came to sing. It went to our hearts, the start of a wonderful friendship between our countries."

Listening to the song today, it's easy to understand its appeal then. It remains hauntingly beautiful, a wistful paean of love with a tinge of sadness.

She had much to be sad about. She had suffered sexual abuse from her father, and she had spent the war in flight from the Nazis, leaving Paris for the south and then dodging to hide from collaborators who would have handed her over to her murderers.

With the war over, she returned to Paris and took up singing and piano lessons at the Paris Conservatoire. But it was cabaret to which she was drawn, and the world of Edith Piaf and then Jacques Brel. Her big breakthrough came in the early 60s with "Barbara chante Barbara".

And Goettingen. In Germany, she was loved for the love she had extended to them. In France, she was a star. Streets were named after her there too. A stamp had her face on it. When she died in 1997, a quarter of a million mourners went to the funeral.

But all that is just the ephemera of showbusiness - the hits and the publicity and the pictures in the paper of her smouldering in dark glasses.

'Her songs stroke the brow' Soft, silky and confidential, her voice never rages like Piaf's nor goes Gitane-blue like Jacques Brel's, her patron. Her songs stroke the brow and disturb the unconscious. Like Mahler and Freud, she quotes a hint of nursery rhyme to evoke innocence and its corruption. Yet she is never harsh or cruel. Her greatest love - "ma plus belle histoire d'amour," she would assure adoring audiences - "c'est vous," her voice breaking on the last monosyllable. For Barbara, music was the element that bonds the lonely to the whole. British music critic Norman Lebrecht Read the full article in Standpoint

The part that still matters is that song. After all, which other singer could claim to have changed the world and for the better?

"Goettingen" was recorded just after one of the big political speeches of the century. President Charles de Gaulle of France went to the German city of Ludwigsburg and addressed the "youth of Germany", again in their own language.

"To you all I extend my congratulations," he said. "I congratulate you for being young."

He had spent much of the war in London as the exiled leader of the Free French and returned to France as the German enemy was forced out - so his speech in German was important. The historians mark it as significant.

But which is more important - the speech of the General or the song of the girl?

You can follow the Magazine on Twitter and on Facebook