PARIS — Surrounded by a moat and four watchtowers, the ancient Chateau d’Ermenonville is not the kind of place one would associate with a product as mundane as paraffin.

But the discreet European luxury hotel, about 40 minutes outside Paris, was one in a circuit of hotels that served as bases for more than a dozen years for executives from some of the biggest names in oil to fix prices of paraffin, the wax byproduct of crude oil that is used in candles, paper cups, lip balm and chewing gum.

Nine companies — including Exxon Mobil, Royal Dutch Shell, Sasol of South Africa and Repsol YPF of Spain — controlled 75 percent of the European paraffin market, and the other 25 percent often fell in with the pricing structure they had engineered.

The scheme drove up prices to consumers in a plot that probably touched most households in Europe, according to the European Union’s commissioner for competition, Neelie Kroes, whose office levied penalties of more than 675 million euros ($900 million).

In levying the fines in October, Kroes released a two-page statement and no supporting documentation. But a review of dozens of pages of confidential legal documents offers an unusual look inside the workings of a price-fixing cartel.

Most cartels operate in secrecy, destroying documents, encrypting e-mail messages or using prepaid phone cards to erase communication traces. The paraffin cartel was rare in that some members kept minutes and attendance lists. Cartel members e-mailed invitations and sought RSVPs. They booked each other’s rooms and played host to open bars.

Documents found when investigators first raided the companies in April 2005 included handwritten notes on stationery from hotels on the cartel’s itinerary: the five-star Kempinski in Budapest or Chateau de Montvillargenne in the bucolic horse country of Chantilly, France.

“Next price increase May/June 2000,” a Shell executive scribbled in a note after a meeting in Paris.

Tibor Toth, a manager with the Hungarian oil company MOL, and the executive who often kept minutes and attendance, also recorded the prices agreed on in German marks, “Raise in January unless first-quarter quantities are reduced, otherwise raise in season, DM 120.”

The relaxed clubiness of the paraffin conspirators stokes worries about the hold that price-fixing cartels have on European commerce. With Kroes taking action against cartels involving elevators, cement, automotive glass and drugs, total annual fines in the past five years have more than tripled, reaching 2.27 billion euros ($2.95 billion) this year.

In the paraffin case, as in others, some of the biggest offenders walked off with no, or relatively small, fines because they were first in the door with information implicating less-involved conspirators. And, unlike in the United States, in the European Union price fixers do not face the prospect of criminal prosecution.

International cartels

Overall, the number of international cartels has been rising nearly every year since the 1980s, according to John Connor, a Purdue University economist whose studies show that global cartels are bigger and more plentiful in Europe.

The paraffin cartel involved at least 35 sales or product managers. In internal memos they used nicknames for themselves and their get-togethers: the Blue Saloon, after a favorite bar in Hamburg; the Appetizer Meetings; even, for one participant, the Paraffin Mafia. At meetings, they fixed prices and carved up markets for their distinct product lines: extruder, coating wax, liquid slabs, tea-light candles and grave lights used for tombstones.

Most cartels last five years, according to studies, then sputter out amid recriminations over cheating. European regulators suspect this one may date as far back as the 1970s, based on files plucked from some companies involved. Investigators said they believed they had firm evidence to form a case starting with a Sept. 3, 1992, meeting of five participants at an unknown location, according to the European Commission’s confidential 200-page report laying out the evidence.

In the months that followed, a ritual developed, according to the documents. Sasol, the market leader, based in South Africa and with an office in Hamburg, played ringleader and club booster. A product manager, Michael Matthai, issued invitations by telephone, fax and e-mail. Usually it was for a half-day meeting, with dinner the night before along with a cocktail hour, often with Holger Schroder, sales manager for Shell Deutschland, playing host.

At Sasol, where the club was known as “Blauer Salon,” or Blue Saloon, after the Hamburg bar, participants would report back on the gatherings to other executives who kept notes.

The companies “tried to protect their home markets by creating an atmosphere of mutual trust and good will among themselves,” according to a file obtained from Sasol by commission investigators.

The documents show that they shared information about customers, production capacities, sales volumes and even plant maintenance. They talked prices, agreeing on absolute numbers.

Toth, the MOL executive, held a more junior position than other sales managers in the cartel, but according to legal documents he was sent to meetings because he spoke English and German. His notes, written in Hungarian, included careful tables and documents with titles like “Candle Industry Price situation,” listing prices for a variety of waxes and the notice of a new price structure.

Memorandums outlining the agreements contained insider references to some of the biggest paraffin customers — the candle-makers Iberceras of Spain and Bolsius of the Netherlands — marked with prices by their names.

Suspicions

Customers may not even have noticed because there was never a uniform price increase, just agreement on what specific companies would charge.

Some candle-makers had their suspicions. During the 1990s, when the cartel was in full swing, the biggest candle manufacturer in Europe, Bolsius, started looking for better prices in Asia, and decided to build a multimillion-euro, 30,000-ton storage depot in Rotterdam for imports, said Vincent Kristen, the company’s managing director.

But that failed because the company started to detect a curious pattern. “Soon we found we were getting more or less European prices from suppliers in the rest of the world,” Kristen said.

By late February 2005, the cartel started to fracture. It gathered for what would be its last meeting in the brightly colored four-star Hotel Madison Residenz in Hamburg but was unable to come to an agreement on prices.

Three weeks after the Hamburg meeting, the cartel was shattered.

Shell, facing $360 million in fines for its participation in other cartels — involving synthetic rubber and bitumen, a thick form of petroleum — revealed the paraffin scheme to European Union authorities on March 17, 2005. Under European Union regulations, Shell won complete forgiveness for what would have been a nearly $130 million fine, as calculated by the commission. Other companies — some far less implicated — faced fines eventually totaling nearly $900 million.

A series of raids followed in the weeks after Shell talked. Perhaps the richest trove of evidence came from MOL headquarters in Hungary, where investigators discovered Toth’s files with a series of notes on hotel stationery arranged in chronological order.

Sasol pressed for leniency the day after the raids concluded on April 29 and received a 50 percent reduction, lowering its fine to the equivalent of $423 million. More limited discounts were meted out to Exxon Mobil and others.

Since the trustbusters issued the fines, chastened top executives have apologized, with several saying that they had unwittingly inherited cartel membership from smaller companies they acquired or that their managers acted without company knowledge.

Sasol’s top executives blamed rogue employees.

The commission argued that senior managers should have investigated the real purpose of the meetings since attendees submitted expenses.

A spokesman for MOL initially said the memo writer, Toth, left the company two years ago, later conceding that that information was incorrect. A colleague of Toth’s in Hungary said he was working there till October, the month the sanctions were announced.