I stood there taking it in: the angles of the buildings, the contrast of the darkening sky and the soft electric lights, the energy and anticipation swelling here and everywhere across Paris. It was all the more thrilling for the fact that I had been here, at this precise intersection, who knows how many times before, but had never quite seen it this way, so alive, so pulsing with potential. Tourists, I knew, lurked nearby, and Parisian scenesters were massing outside bars down the street, too, but the magic of a great neighborhood in this city is that it feels as though it exists for you alone.

Of course, I was not yet ready to be in an exclusive relationship with Montmartre, and since this was Paris, what’s a little flirting between neighborhoods? Perhaps I could find the same happiness, or better, in a place like the 15th Arrondissement, a mostly residential area in southwest Paris that has, as far as I can tell, not a single tourist attraction — no monuments, no cultural institutions (unless you count the Cordon Bleu).

What it does have is real, normal life, which can be as appealing as the “Winged Victory” in the Louvre. For an afternoon I zigzagged among eminently pleasant squares and small parks, resting here to eat a ham sandwich (procured from a boulangerie that placed ninth in last year’s best baguette competition), pausing there to observe the goings-on. Well-dressed friends posing for wedding pictures. A 3-year-old riding a scooter under the supervision of his parents and grandparents. Joggers and sunbathers and teenagers speaking indecipherably slangy French. The sun shone warmly, and I drank an Orangina.

Every once in a while, though, I got a brief glimpse behind this idyllic curtain. As I walked up near the Seine, I passed an old brick high school, glanced down the road to my left and stopped in my tracks. There, hidden until now at the end of the street, was a modernist skyscraper, the Tour Evasion 2000, rising awfully, dejectedly, above its surroundings. And yet it charmed me — so rundown, so out of place in what we think of as a grand, pristine belle époque city. Beyond the tower, stuck between a busy road and the quais of the Seine, was a narrow strip of parkland, a group of homeless immigrants encamped at one end, a nearly naked woman sunbathing at the other.

From there I turned back east, where suddenly the landscape became oddly familiar. Right! Here, still in the 15th, was 47, rue Fondary, where 13 years ago my then-girlfriend, now-wife, Jean, had lived as a student, and down the street the Hôtel Fondary, where we’d spent a night after locking ourselves out of her apartment. That was the first in what would be a long series of travel-related near-disasters — our calamitous Mexican road trip, our jet-lagged toddler’s miserable Taiwan visit — and while I remembered it now fondly, I also felt strange. I’d been whipsawed back and forth between the new and the nostalgic — and I kind of liked it.

This disconcerting though pleasurable phenomenon — the past inserting itself into the present — happened again and again. Another day, back on the Right Bank, in a part of the 12th Arrondissement I would’ve sworn I’d never visited, I stopped for lunch at a cafe, Au Va et Vient, and at one of the outdoor tables enjoyed a hearty bowl of duck confit with sweet carrots while the man next to me distractedly tried to read a Paul Theroux book. Nothing I could see on the broad boulevard — trees, fountains, people strutting purposefully into the Métro — gelled into memory. But afterward, I walked a half-block and found myself at Raimo, an ice cream shop founded in 1947 that also sells sacks of toasted almonds, a lesser-known delicacy that a friend turned me on to in 2009.

Then, just around the corner, I found a mysterious parklike path that led who knows where. Actually, I realized after a few minutes of following it, I knew exactly where. This was the Chemin Vert, the green highway that wends surreptitiously across the 12th, sometimes below street level, sometimes over an old viaduct and occasionally cutting right through buildings. And I’d certainly walked it before. In fact, Jean and I had dined beneath it, at Le Viaduc Café, a trendy spot (or so we thought) back in 1998. And I’d probably ordered duck confit then, too.