It's 200 years since the Duke of Wellington bought the grandiose Hôtel de Charost in Paris, a few doors down from the Elysée palace. And if you want to get to know the secrets of a stately home, I always say, just ask the butler, writes Hugh Schofield in this report from BBC News.
Happily the British embassy in Paris - the sumptuous architectural pearl that is the Hotel de Charost - boasts a butler who is in every way befitting of his charge.
I say butler, because that's how he's referred to on his business card, but in fact Ben Newick is rather more than that. Head of embassy administration, I guess, would be modern business parlance - except it sounds so grim.
So let us stick with butler, and let us stick with the wonderful Newick as he conducts me around the British ambassador's residence in Paris (not technically the embassy any more because that's next door).
It was built in the 1720s when the Rue du Faubourg Saint-Honoré was a winding road that passed through fields and market gardens to the village of Roule.
For our purposes the hotel comes into its own when it's bought in 1803 by the wayward Pauline Borghese, sister of Napoleon, wife of an Italian prince and by all accounts a bit of a wrong 'un.
In a history of the embassy, we read that at her levees or receptions Borghese liked to walk around naked in order to be admired; a "magnificent black man" carried her into and out of her bath; and if she felt cold, she warmed her feet in the decolletage of a lady-in-waiting lying on the floor.
She can't have been all bad though, because the house as we see it today is basically hers. Much of the furniture - Empire style - is what she acquired, as are the silk damasks on the walls.
In one room, next to a bed that was later slept in by both King Edward VII and the late Queen Mother, there's a stunning framed mirror known as a psyche. I can just imagine the narcissistic Borghese twisting round to get a rear glimpse of her own stunning frame.
Napoleon himself used to come to the house to have assignations with one of his sister's ladies-in-waiting, a certain Madame de Mathis. He came in by the garden, and they made love somewhere near where the current ambassador and his wife like to take their tea.
Time is too short to describe the beauty of the Hôtel de Charost. Suffice to say that in all its wonderful salons, the marbled hall, the ballroom, the state dining room, and the Duff Cooper Library, it combines the elegance of classical French design with the warmth and comfort of the British feel.
In 1814 Borghese left to join her defeated brother on Elba, but before doing so she secured the sale of the hotel to the commander of the British Army the Duke of Wellington.
He paid her in instalments of gold louis, which Pauline loyally passed on to Napoleon - so it can truly be said that the emperor's dramatic comeback that climaxed the next year at Waterloo - was partly financed with British lucre.
And so Mr Newick's tales roll on. Here's a lock of hair of Napoleon, next to it, here's a lock of hair of Wellington.
Did you know that according to British etiquette cutlery has to be laid face up (fork prongs in the air), but in France it's vice versa - prongs down. It causes no end of raised eyebrows with some of the guests.
And today the current ambassador Sir Peter Ricketts lives in a modest flat in a small part of the building. It's a blessed release for everyone, says Newick. At last the ambassador's got a kitchen of his own and doesn't have to summon the staff for a boiled egg.
Read more of this report from BBC News.