It was One of Those Days in Paris.

When the sun is breaking through cottony clouds and everyone is smiling and the world is a wonderful place — or at least it is as viewed from the little park named Square Jean XXIII on the tip of the Ile de la Cite.

Let’s take a fast walk around the square.

We approach it from direction of Ile Saint-Louis, via the Pont St-Louis, which spans the narrow channel of water that runs between the city’s two main islands.

On the bridge, when the sun shines and tourists are wandering, buskers are sure to assemble. This afternoon, we have a middle-aged man playing the accordion (La Vie en Rose, I’m sure), and a guy in a fedora and coat singing French love songs.

The former entrance to the square, on the northeast corner, is closed. A fence has replaced the swinging gate, and to enter we continue along the side of the park and enter at the northwest corner, where most tourists enter the square, having exited Notre Dame cathedral, the main lure to the island.

To the right is the back of Notre Dame, and the famous flying buttresses, which were quite the thing in the 13th century, when most of the construction of the church went on.

Tourists tend to cluster just past the Fountain of the Virgin, and take pictures. Of the buttresses? Or just the back of Notre Dame because people tend not to go there. I accidentally photobombed lots of people during my 15 or so laps because my belief is that people exercising do not have to stop for photos.

The tourists represent many more continents than they once did. A group of Americans led by a guide holding aloft a red umbrella, Chinese in twos and threes, Arab families with the women covering their heads. No one is in a hurry. Many of them are eating ice cream cones.

On the right are three benches. The first has a woman of perhaps 25, sitting with great posture, studying what looks like a textbook, with a pen in her right hand. She is wearing the ankle boots that seem to be the only new fashion expression this year, a gray sweater and black tights. Her hair is dark but she is very fair.

The next bench has two older women, sitting and talking quietly. They have been here before. They are resting, but also commenting on the tourists.

The third bench has three young women who are dressed for a party, even though it won’t be dark for more than four hours. They expect to be watched.

Turn the corner around the big tree, and ahead are the 10 benches facing directly into the afternoon light, and the sun is like an elixer when it breaks through the crowds. The people glory in it and turn up their faces toward it, like daisies.

Before the next turn, we note the southeast entrance, where scores of tourists are passing in and out through a gate, and they are serenaded by a man with a guitar, sitting with his back to the Pont de l’Archevech, another little bridge. This one has thousands of locks attacked to its fencing. (For good luck.) The metal glows in the light.

We pass a small building where the park attendant once stood, past benches in the shade. And towards the corner with the vanished gate. The sun is shining on the final two benches, and a woman reading a newspaper is soaking up the rays.

A turn into the rows of trees, and the first half of the fourth side is covered in a rubbery surface because three bits of equipment are up for children to enjoy. The first is a sort of jungle gym, not often used. The second is a single swing, and a father is pushing his excited son as high as he can go. The boy is laughing. The third piece is a metal disk, about five feet across, tilted at about 30 degrees — so that those riding the disk, which spins, go up … and then down. It requires the help of someone, pushing. I would like to ride it, but it’s a kid thing.

The rubber surface ends, and now we are in the shade of a lane between two rows of trees. A man in a coach is framing a picture with a camera augmented by a telephoto lense. Across the path from him is a young woman, perhaps 30, who appears to be reading and unaware of the guy across the way. It seems like an invasion of privacy … until a later lap reveals the man with the camera is with the woman, and she was posing for him by pretending not to pose.

People come through in waves, and often stop to aim cameras at Notre Dame, and I do the same, trying to guess what they are looking at. Flying buttresses can’t command that much attention, can they?

Grinning groups pose, with the fountain behind them, and Notre Dame looming over the whole of it. And some sit for a moment, when the sun appears, and on they move, paying no heed to the guy in athletic shoes. One small group seems to be playing a sort of bowling game; they set up pins after each roll.

The pervading sense is happiness. Joy, even. For many of those who pass through the park, it must be their first visit. They are wide-eyed, and happy to be with whomever they are with, and at peace with each other and the world. Never is heard a discouring word.

It was one of those days. A few here can be too hot. Many will be cold and gray, and the wind will whip up dust on the paths — unless they are muddy from rain.

In this one, it is just kindly sun and shapely clouds. We are a sort of United Nations of people appreciating the heart of Paris. Just being there. Not doing much of anything other than soaking it in.

It is a glorious day.