President Nicolas Sarkozy promises to add a green stripe to the French tricolour today in a speech which will place France at the cutting edge of the fight against global warming. That, in any case, is the theory. The contents of the President's speech will be decided this afternoon at the end of an unprecedented two-day conference and consultation exercise, which is intended to shape France's approach to everything from carbon emissions to pesticides and bio-diversity.

Comments after the first day of the conference yesterday suggested that radical proposals to limit carbon emissions would be included in the President's speech. The ecology minister, Jean-Louis Borloo, said France would halt all "significant increases" in airport or motorway capacity. Many long-distance lorries would be forced off the roads within three years and put on a new network of internal "train ferries". Standards for the insulation of homes, and above all public buildings, would be increased enormously.

President Sarkozy is under pressure from environmental lobby groups – and his own campaign promises – to propel France into the forefront of the struggle against climate change. He is equally under pressure from industry to safeguard a stuttering economy and from his own centre-right party to avoid angering a nation of car-owners.

Many radical proposals were placed before the first day of a round-table conference at the Ecology Ministry in Paris yesterday: a freeze on new airports and long-distance motorways; a cut in speed limits on French roads; an ambitious new programme of high-speed railway lines; draconian new standards on insulation of houses; and a bold programme to increase renewable forms of energy.

Other parts of the conference will discuss a sharp boost in bio-farming in France, new restrictions on pesticides, a freeze on genetically modified crops and new "green lanes" through the French countryside to allow wild animals to move more freely.

How many of the more radical proposals will survive to reach President Sarkozy's speech, and influence government spending programmes, is unclear.

Some green pressure groups were complaining yesterday that the conference was likely to bury some of the more radical ideas produced by four months of consultation. The suggestion of a cut in speed limits already seems to have fallen victim to the electoral fears of M. Sarkozy's centre-right party, the Union pour un Mouvement Populaire (UMP).

The Prime Minister, François Fillon, opening the conference, said France was inventing a "new form of governance" which he called "a green revolution" and an "ecological democracy". However, even moderate campaigners warned that the meeting might result in a large increase in emissions of hot air, rather than firm policies.

The respected French TV ecologist, Nicolas Hulot – a confidant of the President – warned last weekend that M. Sarkozy was under "unimaginable pressure" from industrial and political lobbies to limit the scope of his concluding speech today. "We don't just want marginal proposals. We want something operational," M. Hulot said.

France has a mixed record on environmental issues. It is broadly on course to respect its Kyoto carbon-reduction targets and emits about 20 per cent less carbon than the UK, for roughly the same population, but has fallen behind Germany and other European countries in the use of wind power and the insulation of homes.

(By John Lichfield, The Independent, 25/10/2007