PARIS (Reuters) - Four tobacco companies operating in France manipulated tests to conceal the real level of nicotine and tar contained in cigarettes, endangering the lives of smokers, a French anti-smoking organization alleged in a legal complaint.

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The allegations by the National Committee Against Smoking (CNCT) target the French branches of Philip Morris, British American Tobacco, Japan Tobacco and Imperial Brands Plc.

In its complaint, dated Jan. 24 and seen by Reuters on Friday, the CNCT says cigarettes produced by the companies contain tiny holes in the filter that are designed to ventilate the inhaled smoke under test conditions.

When the cigarette is smoked by a person, however, the holes are compressed and largely covered by the smoker’s fingers or lips, causing the smoker to inhale harder and increasing the intake of nicotine and tar, the CNCT said.

“Such a device tricks smokers because they are unaware of the degree of risk they are taking,” the complaint states.

A spokesman for Japan Tobacco said the company was surprised by the allegations, which it had learned of through the media.

“We declare all the ingredients in our products every year to the Ministry of Health,” Japan Tobacco said in a statement.

“The tar, nicotine and carbon monoxide levels are analyzed several times a year by the National Laboratory of Metrology and Testing, with the approval of the Ministry of Health, to ensure compliance with regulations.”

Imperial Tobacco’s Seita subsidiary said: “We respect European standards and our cigarettes are tested by an independent laboratory.”

British American Tobacco France said it too adhered to regulations and that all its tobacco products were subjected to “rigorous, independent and transparent tests”.

Philip Morris France declined to comment.

The anti-smoking organization said real nicotine levels were five times higher than shown in the tests, while actual tar levels are two to 10 times higher.

It was not clear from the 34-page complaint how the CNCT arrived at its calculations.

The allegations echo the use of so-called "defeat devices" by car makers such as Volkswagen VOWG_p.DE to mask high pollution levels when being tested in labs.