Derrière Le Rideau is a Paris event organiser that produces made-to-measure libertine evenings across the city and the surrounding region. It is run by Zoheir, who introduces himself simply as Z — the name he says everyone in the libertine scene has used for him since 2009 — and he has been organising bespoke events in and around Paris for those years.

The organiser is emphatic about what it is not. In its own words it is not a libertine club, not at all: rather than opening a room to whoever arrives, it prefers to build each evening to order and on request. It puts the volume at somewhere between 300 and 400 events a year, ranging from the most confidential to the largest, and from three people to two hundred and fifty — all of them, it stresses, for consenting adults.

Rather than a single address, it works across several rooms, with a headquarters it calls La Factory. The team around Z is described as a group of women and men as taken with culture as with sex, fond of dinners and of debate — always after the fact, as the site puts it — whose conversation and humour give the gatherings their particular atmosphere.

It presents itself as a professional operation rather than an informal scene: the business is declared and insured, and it describes its work as a service it takes seriously. Alongside the open evenings it will build an event to a guest's own brief, and it runs a paid subscription for members.

Dates are announced through the organiser's own events calendar, which can be subscribed to by iCal, and details are handled directly by message. Because each evening is arranged individually and the room changes with it, check the organiser's own site for what is coming and where.