An elaborate price-fixing scheme has forced French yogurt lovers to pay through their nose, according to a ruling by the country's competition watchdog, which fined 11 dairy companies 192.7 million euros ($204 million) on Thursday.

The antitrust authority's investigation lifts the veil on six years of backroom deals cut in private apartments, hotel suites and on secret phone lines, involving the cream of the crop of France's yogurt industry.

From 2006 to 2012, the cartel, representing 90 percent of the French yogurt market, colluded on price hikes on anything from desserts to fresh cheese and cream, with some bumps as high as 5 percent.

The companies include popular brands Lactalis and Yoplait, the Authority for Competition said in a statement.

Whisteblowers walk free

It was also Yoplait - owned by US General Mills and French Sodiaal - which tipped off authorities, thanks to a provision of French law allowing companies to report their own price-rigging activities in exchange for reduced punishment.

The penalties range from 300,000 to 56.1 million euros. Yoplait was facing a 44.7-million-euro fine, but eventually walked free after cooperating with regulators. Another company, Senagral, was also rewarded for its collaboration, which saw its penalty cut from 101.3 million to 46 million euros.

Lactalis vowed to appeal the decision, saying in a statement that the fines "overestimate in an obvious way the gravity of what happened, and their impact on the economy."

Industry sales at large and mid-sized grocery stores was worth approximately 5 billion euros in 2013.

pad/hg (AP, dpa)