PARIS—One of the oldest tropes in travel writing is that finding the hidden treasures or secret wonders in any culture is the ultimate calling of the savvy tourist. We all know that’s true, but I was sharply reminded of it last week here in one of the great capitals, where ardent tourists routinely mount intense hunts for the most charming tucked-away sidewalk cafe, the cutest little book store, the best little hunk of goat cheese this side of Kurdistan.

I’ve stayed in the Oceania hotel on the edge of Issy for three of the past four years now. My only complaint has been that, for some reason, it was impossible to find a good four- or five-mile route for a morning run anywhere near the hotel. Years ago I tried to develop a route—and almost got run over for my trouble by a lorry as I jogged along a narrow strip of dirt along the river, some sort of scrap metal yard on one side, a busy road on the other. So I gave up on the idea of running while here.

Then, early during this year’s trip, I happened to notice a sign alongside the “Aquaboulevard” complex and the adjacent helicopter landing field just down the road from my hotel.

Aquaboulevard is the kind of high-rise indoor mall you could expect to find in someplace like Tampa, and it has its own attached outdoor water park. Yeah, with its “Forest Hill” Club, McDonald’s, and 16-screen cinema, among other things, Aquaboulevard probably is as unappealing to an experienced to a romantic traveler as I’m making it sound. But then, the place seems to be very popular with locals, and especially the kids, and there’s no law saying the French have to stick with crumbling but quaint apartment buildings with lovely window shutters, or put an accordionist on every street corner, just to keep the Francophiles happy.

Anyway, the sign tucked between Aquaboulevard and the soccer-field sized heliport read, “Parc Omnisports Suzanne Lenglen.” How did I not notice that before? Beneath the sign, a simple turnstile and a wide, paved pathway led into the park. The green refuge is as sprawling as it is well-hidden in plain sight.

The circular interior path is roughly a mile-and-a-half long and it winds its way over gently undulating hills alive with fora, including some spectacular, well-tended flower beds. There are tennis courts, a couple of rugby fields, basketball courts, soccer fields, and a rubberized Olympic spec track.

While running these two weeks, I’ve seen an elderly Chinese lady on the basketball court reach in and make a quick, nifty steal from a 10-year-old curly-haired French boy who happened to be dribbling a soccer ball. It was sport’s equivalent of the ultimate mixed metaphor. I imagined that the crone was no coach, merely a babysitter.

Running past the tennis courts reaffirmed my feeling that, per capita, France probably has more male individuals who play tennis in short shorts, black socks, and running shoes than any other nation on earth. This is particularly odd, given that French men are not without the style gene (more about that a little later).

I also suspected, from the syncopated heavy “thwock!” that issued over and over from the courts, that players seem to have an aversion to using anything but old tennis balls. Presumably, this is the end result of some sort of green initiative promoted by the city fathers. I don’t believe that a No. 2 optic yellow tennis all is bio-degradable, although it’s pretty easily re-cycled into yellow Labrador retriever dung if you give the dog half a chance.

Ah, that French sense of style. I never cease to marvel at it. This year I was particularly struck by the penchant French men have for yard-long scarves in every material from white silk to calico cotton. They’re dangling around the necks of men everywhere; there are even a few scarf-wearers here in the International (non-French) Writer’s Room at Roland Garros.

I suppose there’s something notionally dashing, or a tad risqué, about a scarf-wearing dude, and I’ve wondered if there’s some significance in the different ways the fellas tie or knot their scarves.

Maybe the scarf is meant to make the wearer look like a World War I pilot—maybe even Roland Garros himself. Unfortunately, when I see some of these guys in scarves, I can think only of the comic-strip character Snoopy. The only thing missing is the leather helmet and aviator goggles. Whatever the case, even you Francophiles must surely admit that it’s kind of weird to see a man walking around in a Metallica t-shirt and baggy jeans with a long scarf loosely knotted around his neck.

Today I ran mostly on the cushioned track, to save wear and tear on my beat-up knees. There were a couple of elementary school classes (I’m guessing fifth or sixth grade) out there, playing a clever hybrid sport I’ve never seen before. We’ll call it Tenniball. It’s basically baseball played with a tennis ball, while the batter uses a tennis racquet instead of a Louisville Slugger.

I could tell even without stopping to watch that the genius of Tenniball is that nobody strikes out. Ever. Heck, even the Milwaukee Brewers’ Mark Reynolds would never whiff if he could use a tennis racquet. Improvising on the rugby field, one corner was used as home plate (infield dirt is a luxury not everyone can afford), and the bases were roughly set in the familiar diamond shape.

The kids squealed with delight and anxiety each time someone made contact and triggered the mad rush to catch or retrieve the ball—and try to throw or tag out the runner. Perhaps the most amusing part was the way the boy hitters all chose to slide or dive to whatever base they were trying to reach. I had half a mind to go and tell them that sliding wasn’t obligatory, especially when you’re beating out a single. But it’s their game, not mine, so who’s to say?

Doing laps at a pathetic pace (I burn through a mile at a blistering pace of 12 minutes, give or take), I came to the end of my workout and reluctantly left behind the carefree habitués of the Parc Omnisport Suzanne Lenglen. The park may not be the most travel-magazine feature ready little “secret” Paris has to offer, but it’s good enough for me.