View of Paris and the Eiffel Tower© Rex

Ten French dairy firms have been fined more than €190m (£136m) for running a cartel to fix prices.

France’s competition watchdog has ruled the companies were secretly rigging the market for supermarket own-label yoghurt, soft cheese and desserts between 2006 and 2012.

Business officials met in hotels, favourite cafés and even their own homes to agree price hikes for retailers and the reasons behind them.

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They carried secret mobile phones dedicated to the cartel, with company names not appearing on the bills.

Firms also distorted new supermarket tenders by forming non-aggression pacts, dividing up volumes between them and freezing their market share.

All decisions were recorded in a secret notebook, later handed to investigators by yoghurt maker Yoplait in exchange for leniency.

The French competition authority said the fines matched the gravity of what took place and the damage to the economy.

“This cartel was so widespread as it covered the whole country and the companies implicated represent more than 90% of the own-label dairy market,” a statement said.

“Its secrecy and sophistication [changing meeting points regularly, dedicated mobile phones, gathering in private homes] make what happened even worse.”

Some of the reports revealed by the authorities sound more like spy stories than food industry negotiation.

For discretion, the companies took turns to book hotels for meetings. And the boss of Novandie told investigators how meetings took place in his Paris flat or close by.

“The apartment in Paris’ sixth arrondissement belongs to my family,” he said.

“We preferred to meet in a café like ‘Le chien qui fume’ [The Smoking Dog] on the Boulevard de Montparnasse.

“The guys from Lactalis sometimes came into my flat to continue the conversation or smoke a cigarette.”

The firms fined were: Senegral, €46m; Novandie, €38.3m; Lactalis Nestlé Ultra Frais MDD, €56.1m; Lactalis Beurres & Crèmes, €4m; Maître Laitiers du Cotentin, €22.9m; Yeo Frais, €12m; Laïta, €8.1m; Alsace Lait, €3.6m; Laiteries H. Triballat (Rians), €1.4m; and Laiterie de Saint Malo, €300,000.

Yoplait was let off from punishment as the first to bring evidence of the cartel to the authorities.

Senegral also had its original fine cut in half for working with the watchdog.

A fortnight ago, 11 Spanish dairies were fined €88m for fixing milk prices paid to farmers over 13 years.