We came off the bridge onto a boulevard, broad and divided, where buildings of pale stone with sloped mansard roofs and tall, graceful French windows shared space at the edge of the pavement with more modern offices, shop fronts, and flats. I had an impression of tall, bare-branched trees and bright Christmas lights strung over doorways and dangling like icicles over the edges of awnings. They sparkled against the blue light of the evening and made the whole street look decidedly festive.

“It’s pretty,” I said.

“Wait till you see the Maison des Marronniers.”

“That’s the name of the house?” I liked houses with names. “Are there actual chestnut trees?”

“Why would you ask that?”

“Because that’s what marronniers are.”

“Ah.”

“How can you spend so much time visiting France without knowing the language?”

“We can’t all be linguists,” she commented. “How many languages do you speak now? Twenty?”

“Other than English? I only speak two.”

“No, it’s more than that, surely? You’ve French, thanks to Ricky”—my childhood best friend, who’d moved over from Normandy when we’d both still been in nursery school, and in whose house, next to our own, I’d spent most of my after-school hours, in the bustle and warmth of his French-speaking family—“and Swedish, from when you were keen on that Swedish chap. What was his name?”

“Vendel.”

“Ah, Vendel, yes. Charming man.” That, I knew, was pure sarcasm. Jacqui had never liked Vendel. She added, “But then you took courses in German, and—”

“I know a little of four other languages, but I can only speak two.”

Jacqui gave me a sidelong look I couldn’t read as she slowed the car and steered us through a narrow gate within a high wall fronting on the pavement.

Claudine Pelletier, I decided, must have either married money or been born to it. Because the house that faced us was a cut above the pay grade, I felt sure, of a photographer.

The house was old. Not ancient, but designed with grandeur and a certain elegance that made me think it dated from the century before the last. And it was much, much larger than I’d thought it would be, stretching long across the garden and rising up a full three stories, with an attic above them, revealed by two round windows set within the steep slant of the slate-gray roofline. There were chimneys—three, that I could count—and rows of gorgeous windows in the classic French style: tall, with lacy black wrought iron balconies for all except the ones at ground floor level, where a broad stone terrace with a carved-stone railing curved along the front facade and dropped a wide and generous fall of grand stone steps to welcome visitors.

The chestnut trees were here as well. We drove beneath a massive one with black and leafless branches as we came into the circle of the drive, and there were others standing like a row of sentinels within the high walls shutting out the larger world with all its noise and bustle. In the twilight, all that pale stone with small accents of dark brick and those grand windows gleaming warm with golden light gave the Maison des Marronniers the look of a château.

It looked like something of another age. It shouldn’t have been standing at the corner of a busy street. It should have been out in the country, as it must have been when it was built. It wanted gardens all around it, and the clop of horses’ hooves, and graceful carriages arriving with their guests, not our rented Peugeot rolling up to those impressive steps and coughing to a halt.

There had been no one on the terrace when we’d stopped, I would have sworn to it, but when we had stepped out and got our luggage from the boot and turned around again, we met a woman coming down to greet us.

I braced myself a moment, till I realized this was not Claudine, but someone nearer my own age, with straight black hair cropped closely in a stylish cut that framed her smiling face. Her English, when she spoke to Jacqui, was cautious and came with the handshake reserved for acquaintances, not with the bise—the light double or triple or even, in some places, quadruple kiss that was used when you’d moved beyond that and become more informal and friendly. “You have had a good journey?”

“Yes, lovely, thanks. Sara,” my cousin said, “this is Denise, Claudine’s housekeeper.”

I should have guessed that a house of this size would need people to run it. I held out my hand for the housekeeper’s handshake as Jacqui said, “Sara’s my cousin. The one who’ll be working here.”

Denise smiled. “Yes, of course. You are… I am so sorry, I don’t know how you say in English…the déchiffreuse.”

I answered her in French, to make it easier. “The code breaker, that’s right. Though not a trained one, I’m afraid. It’s just a hobby.”

When she didn’t answer right away I worried I’d said something wrong, but then her smile broadened. “You speak French.”

“Yes, I do. I learned it as a child.”

“You speak it beautifully.” And then, to Jacqui, dropping into English for her benefit, the housekeeper repeated, “She speaks French.”

My cousin smiled, in turn. “She does. But I’m still hopeless at it, so feel free to use her as a translator.” She glanced towards the partly open front door, just behind Denise. “Is Claudine not at home?”

“She is working. But she will be back in time for dinner. Please, come in. I have prepared your rooms.”