Six of Paris' most prestigious hotels have been fined for sharing commercial information, helping to keep prices artificially high.
The Crillon, Bristol, Meurice, Piazza Athenee, Ritz and George V hotels were accused of operating a cartel by competition regulators.
A four-year investigation found they shared details of room rates averaging more than 700 euros (£480) a night.
The six establishments have been fined a total of 709,000 euros.
Luxury
The Competition Council found that the six hotels had exploited their position at the luxury end of the market to effectively regulate prices.
The establishments were in a league of their own due to their central location, exceptional accommodation, high-class restaurants, facilities such as swimming pools and high staff numbers.
Room rates ranged from a minimum of 500 euros a night to 6,000 euros for the most prestigious suites.
But the watchdog concluded that executives had regularly shared confidential information, including details of room rates and marketing plans, for the hotels' commercial benefit.
"Taking into account the oligopolistic nature of the market, the Council considered that these practices had altered the normal rules of competition, favouring an unfair market," it said in a statement.
The Hotel Crillon - built in 1758 for King Louis XV - has been ordered to pay 248,000 euros, the single largest fine.