Good news may sometimes come from unexpected places. ;-)
The official institution declared the bill unconstitutional for two related reasons: the tax was meant to primarily affect gasoline and heating oils - while giving exemptions to 93% of CO2 other sources (including the right of AGW apparatchiks to fly to exotic, long-haul destinations for meaningless CO2 conferences). These irregularities mean that the bill contradicts its own stated purpose, namely the "fight against climate change", as well as the principle of fairly shared tax burden.
The court kept its opinion about the very idea of having a carbon tax in secret which is probably the right thing to do. The French leaders will have to find a different place where to steal EUR 4.1 billion in 2010 than the carbon Ponzi scheme. As far as I know, Sarkozy who tried to squeeze this illegal scheme - violating liberty, equality, as well as fraternity - into the French legal system won't follow the 1793 example of Louis XVI of France so far.
Stay tuned. ;-)