French health experts have recommended a ban on the use of electronic cigarettes in public places where tobacco is already prohibited.
An estimated 1 million people in France are using the gadgets which cigarettes allow smokers to inhale a vapour containing nicotine, but not the harmful toxins of tobacco.
The numbers have increased rapidly in the past couple of years, putting pressure on the authorities to give a ruling, the BBC reports.
A government-appointed committee has taken the view that for heavy smokers, e-cigarettes are a safer substitute.
However the medical experts fear that e-cigarettes pose a threat because they can be seen as encouraging an interest in smoking especially among the young.
The experts also recommend that the same advertising rules as apply to regular cigarettes be enforced for the electronic version, and that they are sold only at approved places.