Such a tax would affect exporters in non-Kyoto industrialised countries like the USA as well as emerging developing countries like China and India.

Taking up a recommendation made by an industry-led EU advisory group in October, Mr De Villepin said he intended to "study the idea" with France’s European partners.  A "concrete proposal" will be put forward in the first half of 2007.

The move aims to put political pressure on major emitters currently without greenhouse gas targets and to protect EU industries with carbon caps from "unfair" competition with non-EU firms without.

"Some countries might be tempted to refuse to participate in renewed efforts after 2012", Mr De Villepin told a press conference on Monday.  "Europe must use its influence to reject this form of environmental dumping".  French environment minister Nelly Olin is to present the idea at the UN climate talks in Nairobi to start a debate.

The French prime minister was speaking following a government meeting aimed at updating France’s climate plan.  He also announced measures to strengthen the polluter-pays principle, including a 10% increase in taxation of industrial and air transport pollution as well as waste.  Possible other measures include congestion charges in major cities.  A tax on coal announced in October will also be introduced in 2007.

Follow-up: French prime minister’s office, plus Mr De Villepin’s speech.  See also report of the EU high level group on competitiveness, energy and environment.