171, rue Saint Jaques, Paris V.
Rue Saint Jacques is unusually wide and straight for a pre-Haussmann Parisian street. It runs south from the tourist magnet of Notre Dame uphill past the old Sorbonne and the even more imperious Pantheon until it narrows and enters a mess of medieval streets at the heart of The Latin Quarter.
Where the buildings either side begin to close in on each other, you will find the usual neighbourhood services essential to French life. The butcher, the baker, the wine shop, the greengrocer, the traiteur and the inevitable hairdresser.
There are chickens rotating on spits, fat butchers with bloody aprons, students grabbing a sandwich between lectures, little old ladies scuttling about for their daily supplies and one of the oldest (and cheapest) restaurants in the city, Perraudin.
It was here, in the Vth arrondisement, back in 1999, that we took our first foray into overseas property ownership.
Our top floor garret at 171 rue Saint Jaques was no more than 350 square feet, built in the17th century and arrived at by climbing 84 narrow, worn, stone steps.
It had a sitting room/kitchen, a bedroom and a terrifying balcony.
From the tiny back bedroom there was an almost Disneyesque view across Parisian leaded rooftops towards the towering cupola of The Pantheon. From the front you looked down on the bustling narrow street.
It had original tiles and an old fireplace, walls that had probably never been straight or square and a charm that felt terribly foreign and yet very homely at the same time.
If I appear to be waxing lyrical, it's because the whole experience was pretty good.
We found the flat through a couple who were friends of friends and ran an estate agency in Paris.
It was in a terrible state, of course, but Issy and Olly, the agents, took charge of the renovation and within a couple of months or so there was a new kitchen, a new shower room (well, cupboard) and crisp clean white walls.
We 'lived' Parisian weekends as often as we could cajole our two youngest children onto Eurostar. At
3 and 10, they weren't really into strolling around The Left Bank looking at the shops and stopping for leisurely lunches. Anything we did had to be 'sweetened' with long trips to the nearby Luxembourg Gardens for ice creams and carousel rides, the occasional day at EuroDisney or lunches of roast chicken and mashed potatoes brought home from the Rue Mouffetard market.
We didn't rent out the flat (no Airbnb back then), it didn't seem worth the bother. The flat had cost us €100,000 plus notaires fees and taxes. And the annual service charges and local taxes were pretty negligible on such a small place.
After so many years, my memories are of course rather rose-tinted. But it can't have been that bad - our son and daughter seem to have grown up sharing our love of the city. Indeed, one of them just spent a happy year there as part of her French degree.
Eventually we sold the flat (much to my regret now) and moved south in search of somewhere our young family did want to go (which, of course, was the beaches and, as they got older, bars of St Tropez).
Why am I reminiscing about this now? Well, not long ago we went back for a weekend to visit our old Paris haunts and pass by our apartment building.
We've been back numerous times since we sold the garret, but this time I wasn't working, we didn't have our daughter to see or friends in tow or anyone other than ourselves to please.
It gave me the chance to properly compare it to our own capital. And reflect on what has changed in both London and Paris.
We had a wonderful weekend. We ate well enough, visited the extraordinary Louis Vuitton Fondation and possibly the smallest concert hall known to man on the beautiful Ile St Louis. We stayed in a great little hotel and wore out our shoes walking all over the Marais, St Germain and the Latin Quarter.
I can't remember a much nicer weekend, if I'm honest.
But, and it's a big but, the city itself looked a bit frayed at the edges, a touch run-down, a tad down-at-heel.
When we first bought the flat, the Metro seemed such an improvement on our own Tube. Today it's the other way round. The Metro looks old, tired, unloved, full of unhappy, slightly shabby people.
Our Tube looks newer, feels faster and seems full of people wearing better clothes, earning more money and with energy.
Above ground, the architecture of Paris is of course (and quite rightly) unchanged. But it's dirtier than before, scruffier when you look closely, and just feels poorer.
Arriving back in London, the opposite is again true. Gliding to a halt in St Pancras is like arriving in the new world. Our gleaming arcades of safe, bright, new, jolly restaurants and shops are a welcome relief after the Gare du Nord's sense of menace and dreadful Eurostar facilities.
London pulses with an energy and style Paris cannot even imagine. Of course we have our poor, our destitute, our marginalised and many, difficult social problems. But London is vastly bigger and hugely more cosmopolitan. It absorbs races, cultures and religions in a way our neighbouring capital never has.
While Paris has atrophied, London has seemed alive to the future.
Wherever you look, whether it's the restaurant scene in Soho, the hipster cafes of Hoxton or the swathes of new developments regenerating run down areas, we are a city of tomorrow whereas Paris has clung to an outmoded and crumbling edifice, both architecturally and socially.
But is that all about to change once again? Is it the turn of Paris to move forward and London to go backwards?
It is certainly beginning to look that way.
Brexit, of course, will almost certainly cast our city adrift from its continental neighbours far more effectively than the English Channel once did. Perhaps the droves of creative, hard working, well-educated young Europeans who have been drawn to London in the past will now head for Berlin, Paris or Amsterdam instead. It will be our loss.
Macron could well be the Blair France so desperately needs. Already he is giving the country a confidence, a swagger and a relevance that it has seemed to lack for so long. If he can translate that into economic reform, Paris will be revitalised.
We on the other hand have perhaps the worst set of political leaders I have ever seen.
The Conservatives seem bereft of ideas, leadership or direction. Riven by endless angst and anger over Brexit, they may retain power but seem powerless to move us forward. Labour, on the other hand, is now controlled by an ultra-left, near Marxist faction (hidden for much of the election) committed to bribing its way back into power with undeliverable goodies for the young.
It's a choice that makes you long for the country to magic up its own charismatic, progressive and inclusive leader. Someone who will take us forwards rather than return us to the catastrophic 70s.
(Where are you, David Milliband, when we so desperately need you?)
But that looks as unlikely as a reversal of the Brexit decision.
What doesn't seem so unlikely, however, is a reversal in the fortunes of these two great cities.
Paris on the up. London on an almost suicidal spiral downwards (in the hands of either party currently).
And that's a shame. I was just getting used to boasting about London.