Vanessa is a brocanteuse: she buys and sells old goods. A natural-born forager, says she. The walls of their apartment are plastered with the kind of things she loves: printed cocktail napkins from a bar in Spain, a leopard-skin carnival mask with gold whiskers, photo spreads from old magazines.

Many of these photographs, laser copied and blown up, are of Rat’s English granny, her unknown father’s mother, whose name was Celia Kidd. Rat’s real name, too, is Celia. She was named after her granny, but everybody except for teachers calls her Rat.

Celia Kidd was a top model in London in the 1960s. There is a black-and-white blowup of her on the kitchen wall from British Vogue, a tall slinky girl, slim as an otter, with white skin and enormous eyes, wearing a poncho made of white feathers, and seemingly nothing else. Her gaze is merry and slightly mocking.

Rat’s father, Gillem McKane, was her only child.

Rat’s favorite photograph is of Celia and Gillem together, when he was a little boy not much older than Rat. It’s a two-page color spread, and it comes from a time when Celia Kidd was married to a British film director.

Celia, older than in her modeling days but still ferociously beautiful, is wearing a brocade fur-trimmed tunic. She is stretched out on the sofa, her long legs dangling over the armrest. Gillem is sprawled on the floor at her feet, drawing a picture. You can’t see his face, because he’s looking down. But he’s got long black hair, and he’s wearing a shirt with a frilly collar. In big letters printed along the side of the photograph, it says in English: “Mrs. Harbison’s drawing-room is midnight blue, a favorite Empire sofa is upholstered in hot-pink velvet.”

Celia and Gillem’s lives were so star-studded you would never have thought they would cross with Rat’s mother’s.

But later on, when Gillem was in his twenties, there was a period when he and his mother used to spend their summers in the Pyrénées-Orientales. They rented a big house on the cliffs above Collioure, which was the village where Vanessa and her parents lived. Celia Kidd would pack the house with her glamorous friends. And for a month in August, Collioure, otherwise rather sedate, would suddenly look as glitzy as Saint-Tropez.

Rat loves hearing the story of how her parents met.

One Saturday night, according to Vanessa, Gillem walked into the nightclub where she and her girlfriends hung out.

“Did you know who he was?” Rat asked.