diggers

I am in the process of selling my property the completion was set for jan 7th 2011 and have just been advised by the notaire to bring the date forward to the 31st dec because of a new property tax applying to all sales from the 1st of jan. the tax is 12%of the gain made. i am French resident and this is my main residence the notaire is fully aware of my status. Would be grateful to know if anyone has heard of this tax, is it part of the new budget reforms?