I’m not a thief, you understand. First and foremost I’m a collector. I have been since I was eight years old, collecting charms for my bracelet, but now I collect individuals; their names, their secrets, their stories, their lives. Oh, some of it’s for profit, of course. But most of all I enjoy the chase; the thrill of pursuit; the seduction; the fray. And the moment at which the piñata splits—

That’s what I love best of all.

‘Kids,’ I smiled.

Yanne sighed. ‘They grow so fast. A blink, and they’re gone.’ Way down the alley, the girl was still running. ‘Don’t go far!’ Yanne called.

‘She won’t.’

Yanne looks like a tamer version of her daughter. Black bobbed hair, brows straight, eyes like bitter chocolate. The same crimson, stubborn, generous mouth, lifting a little at the corners. The same obscurely foreign, exotic look, though beyond that first glimpse of colours through the half-open door, I could see nothing to justify the impression. She has no accent; wears well-worn clothes from La Redoute; plain brown beret at a slight angle, sensible shoes.

You can tell a lot from a person by looking at their shoes. These were carefully without extravagance: black and round-toed and relentlessly uniform, like the ones her daughter wears for school. The ensemble slightly down-at-heel, a shade too drab; no jewellery but for a plain gold ring; just enough make-up to avoid making a statement.

The child in her arms may be three at most. The same watchful eyes as her mother, though her hair is the colour of fresh pumpkin and her tiny face, no bigger than a goose egg, is a blur of apricot freckles. An unremarkable little family, at least on the surface; and yet I couldn’t rid myself of the idea that there was something more that I couldn’t quite see, some subtle illumination not unlike my own—

Now that, I thought, would be worth collecting.

She looked at her watch. ‘Annie!’ she called.

At the end of the street Annie waved her arms in what might have been exuberance or revolt. In her wake, a gleam of butterfly-blue confirms my impression of something to hide. The little one, too, has more than a hint of illumination, and as for the mother—

‘You’re married?’ I said.

‘I’m a widow,’ she said. ‘Three years ago. Before I moved here.’

‘Really,’ I said.

I don’t think so. It takes more than a black coat and a wedding ring to make a widow, and Yanne Charbonneau (if that’s her name) doesn’t look like a widow to me. To others, perhaps, but I can see more.

So why the lie? This is Paris, for pity’s sake – here, no one is judged on the absence of a wedding band. So what little secret is she hiding? And is it worth my finding out?