De Boer pointed out that the 1997 Kyoto protocol, the world's existing treaty on greenhouse gas emissions, took several years to finalise and to come into force.

Workers at the state-affiliated utility Électricité de France and the gas company GDF Suez walked out, as did some employees of banks and big international companies.

In February Mr DE Villepin brokered a merger of Gaz DE France, the state-controlled gas utility, and Suez, a private water-and-power company, to prevent a hostile bid for Suez from Italy's ENEL.