Madame Claude — France's Super-Madam to Presidents and Kings

The autumn leaves have barely finished falling on the Avenue Foch when the black Citroën DS pulls to the kerb outside 18 rue de Marignan, in the eighth arrondissement, a narrow, perfectly bourgeois street running behind the Champs-Élysées and just above a branch of the Banque Rothschild. The driver — a mid-level diplomat attached to the Quai d'Orsay — presses the intercom. Upstairs, a compact blonde woman in a gray cashmere turtleneck lifts the receiver. " she says.

That greeting — curt, almost bored — is the most famous two words in the history of French vice.

Inside the apartment, the phone bank — four, six, sometimes eight handsets — occupies a long table covered in a cream cloth. Beside it: a Hermès diary, a stack of index cards indexed by name, and a single ashtray she never uses. The year is 1969. Georges Pompidou has just been elected President of the Republic on a wave of post-soixante-huit conservatism.

Alexandre de Marenches will soon be appointed to reform the SDECE, France's external intelligence service, with orders from the Élysée that amount, in the telling of those who know, to one simple requirement: get us intelligence on the men of power, and make sure the intelligence flows in the right direction.

Madame Claude's apartment is one of the most discreet nodes in that network. She knows it. The men at the Quai d'Orsay know it. The men at the Élysée know it.

And tonight, as on most evenings, she will make perhaps thirty calls — matching a Scandinavian graduate student with a visiting arms dealer, a Normandy aristocrat with a minister who has asked for something "cultivated and a little melancholy" — and not one of those transactions will ever appear in any government ledger.

This is France's most expensive secret. Her name — the alias, not the legal fiction — is Madame Claude.

To understand why Fernande Grudet could build the most powerful private intelligence asset in postwar Europe using only a notebook and a telephone, you must first understand what the Marthe Richard Law of 13 April 1946 actually did — and what it conspicuously failed to do.

You must also understand what France was, in 1946, in 1956, in 1966: a country trying to rebuild its self-image from rubble, simultaneously conducting colonial wars in Indochina and Algeria, presided over first by the exhausted technocrats of the Fourth Republic and then by the imperial dignity of de Gaulle, and throughout all of it saturated with the conviction — sincerely held at every level of the establishment — that French civilization represented a higher register of human existence in which the pleasures of the flesh were not vices but refinements.

The law bears the name of a woman who was herself a subject of considerable mythology: Marthe Richard, born Betenfeld in 1889 in Blâmont, Lorraine, former prostitute, former spy, and, by 1945, a Paris municipal councillor with an unexpected appetite for moralizing.

The law she championed closed France's approximately 1,400 registered brothels — the maisons closes — including such landmarks as Le Chabanais on the rue Chabanais, Le Sphinx on the boulevard Edgar-Quinet, and the One-Two-Two on the rue de Provence, where a generation of bourgeois Frenchmen had conducted their evening education. By 6 November 1946, all of them were shuttered.

What the Marthe Richard Law did not do was abolish prostitution itself. In France, the act of selling sex has remained legal to this day. What the law criminalized was proxénétisme — procuring, living off the earnings of prostitution, operating a house. The distinction is fine enough to drive a coach and horses through, and for twenty years after 1946, that is roughly what happened. The brothel owners rebranded themselves as hoteliers.