The National Agency for Health, Food and Environmental Safety (ANSES) said on Tuesday it would make a recommendation that children and heavy users of mobile phones limit their exposure to the devices, with heavy use defined as 40 minutes of conversation a day.

The safety watchdog added, however, that it was standing by existing recommendations for mobile phones, wifi and cellphone relay antennas, saying the electro-magnetic emissions by mobiles had "no proven effect" on health.

The report was put together by a panel of 16 experts, who looked at more than 300 scientific studies that have been published since 2009, when the recommendations were last assessed.

The panel noted some studies that have suggested a higher long-term risk of brain cancer for heavy users of mobile phones.

Last October, an Italian court issued a landmark ruling, finding that a commerce manager was entitled to compensation from his company because the brain tumour he suffered (later removed), was caused by "speaking on a mobile phone up to 6 hours a day for 12 years because his job demanded it."

On Tuesday, ANSES also listed various possible "biological effects in humans or animals," namely disruption to "sleep, male fertility or cognitive performance," which coincided with mobile phone use.

"However, the agency’s experts were unable to establish any causal link between the biological effects described in cell models, animals or humans, and any possible resulting health effects."

"Given this information, and against a background of rapid development of technologies and practices, ANSES recommends limiting the population’s exposure to radiofrequencies – in particular from mobile phones – especially for children and intensive users, and controlling the overall exposure that results from relay antennas," it said.

Despite the absence of a definitive consensus on the health risks associated with mobile phone use, the fast pace of technological development, and the current inability to conduct certain risk assessments meant the agency was recommending a limiting of exposure to radiofrequencies among the general population.

For example, ANSES noted that the "potential impact of communication protocols [such as] 2G, 3G, and 4G networks seems to be poorly documented."

This could cause concern in France, whose 4G network was recently expanded to include 40 million potential users, or 63 percent of the country's population. And in September, Paris rail chiefs announced a plan to roll out 3G and 4G wireless coverage across the region's Metro and suburban rail networks by 2015.

Dominique Gombert, head of risk assessment at ANSES said that heavy use of mobile phones was considered to be 40 minutes or more a day in conversation.

Options for consumers include using a hands-off kit or selecting a phone with lower electromagnetic emissions, ANSES said.  Mobile phones are the biggest single source of everyday exposure to electromagnetic radiation, the agency added. 

Tuesday's report comes after France's Green party, the junior member of the coalition government with the Socialists, in March included in an education bill an amendment for French schools to use "wired" internet access (Ethernet), rather than wi-fi, as part of the digital revamp of the country's schools.

The provision was based on fears about the long-term effects of radiofrequency exposure among children.

For its part, the WHO (World Health Organization) has reached similar conclusions to those of ANSES. "A large number of studies have been performed over the last two decades to assess whether mobile phones pose a potential health risk," the WHO said in a factsheet.

"To date, no adverse health effects have been established as being caused by mobile phone use." It did note, however, that because mobile phones only became widely used in the 1990s, not enough data is yet available to study the long-term effects of mobile phone use.

But, the WHO said, "animal studies consistently show no increased cancer risk for long-term exposure to radiofrequency fields."

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