By Emma-Jane Kirby
The river Seine formed a key part of the backdrop to the three years I spent as the BBC's correspondent in Paris.
Bateaux mouches are open excursion boats for several hundred people
My apartment partly looked over the river and almost every time I opened my window I could hear Edith Piaf belting out La Vie en Rose as a bateau mouche, crammed full of tourists, floated past my window.
For a few beautiful seconds, my heart beat alongside hers... and then she was gone, her little sparrow's voice drowned out by the man on the loudspeaker saying: "Next stop Town Hall and sorry, but there are no toilet facilities on board this boat."
Despite its charm, the Seine has never been able to swim free of such splashes of scatology.
Until the late 19th Century one of the river's principal functions was to serve as the city's sewer, a job she carried out admirably, dutifully transporting dysentery and typhoid to any Parisian foolish enough to ingest her waters.
Today, as a result of concerted clean-up efforts by successive governments, it is alleged that Atlantic salmon have begun to return to her currents.
One hot night last summer I was standing with friends on the bridge by Notre Dame, staring down into the dark ripples of the Seine when a flash of moonlight picked out a large fish below us.
I am no angler, but I can tell you now that the foot-long, blunt-nosed, prehistoric-looking creature we saw swimming slowly downstream shared no common ancestry with the salmon.
Hideous and unsettlingly alien, it swam into the blackness, leaving us all chilled and with a foreboding sense that the river had much bigger secrets to share.
Bobbing just beneath the glassy surface is the sluggish undercurrent of the Seine's dark past.
Throughout French history, from the religious wars to the revolution, the river has swallowed the last breaths of hundreds of unfortunates who found themselves on the wrong side of power.
And far more recently, in October 1961, during the Algerian war of independence, the river was said to have run red after scores of peaceful demonstrators were beaten to death and tossed into the water by the French police.
These days the Seine is carefully patrolled by the river cops and I used to love to watch them in their motorboats speeding up and down the river - until I realised quite what they were fishing for.
In the first year alone of my residence in the city, more than 50 bodies, mostly suicides, were fished from the water.
Straddled by prejudices
There is a great judgemental dividing line between the two very different river banks.
In choosing which side of the Seine you wish to live on, you immediately make a statement about your beliefs and your ideals.
Go left and your sympathies are socialist, your interests aesthetic and your passion, equality.
Go right and you are a conservative, your interests practical and your passion - business and money-making.
Surprisingly, given the ease with which it has taken so many lives over the years, the Seine has been unable to drown the deep-rooted prejudices that straddle it.
Each Saturday lunchtime I used to go for an aperitif at the Maubert market in the heart of the left bank's Latin quarter, where an impromptu club of local people talked politics around the stall of Ibou, a striking Senagalese art seller.
Naturally, being "left-bankers", the talk largely centred on ripping apart the recent actions and speeches of the right-wing President Nicolas Sarkozy while Ibou - who always had a copy of the left-leaning Liberation newspaper or the satirical Canard Enchaine under his arm - skilfully directed the debate.
And then one day last year a stranger jogged past the stall and shouted a greeting to Ibou in passing.The left bankers enquired as to the stranger's identity and, slightly awkwardly, Ibou admitted that he knew him from his "other market stall club on the right bank".
When the shock had passed, one of the women, with nothing short of an anthropological curiosity, asked: "What are they like then, these people on the right bank?"
Drawn to water
I made a strategic decision to choose neither bank in Paris and instead had an apartment on the Ile St Louis, an island floating peacefully - and impartially - in the centre of the river.
I felt very much at home cradled in the bosom of the Seine, but in my building at least three of my French neighbours complained to me they suffered from a chronic insomnia, blaming the swirling, unsettled currents of the water that surrounded them for churning up their sleep.
Since I have moved back to Oxford, I seem to spend a disproportionate amount of time strolling the banks of the river Isis - some strange, atavistic urge drawing me to water.
Sometimes I even catch myself searching for a bateau mouche among the sculling boats and punts.
Early this morning, in the backwash of my slumber, that prehistoric-looking fish I once saw in the Seine suddenly finned into my dreams.
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