The increase in cotisations has exercised my mind for a couple of days now, so I have checked my own financial records : the increase actually arises from the fact that in 2005, there was an abatement (allowance) of 20% applied to Gross Income, which had the effect of reducing the taxable income substantially, and consequently the Revenue Fiscale de Référence. The balance was then taxed at the prevailing rates for the various tax bands. However, in 2006, this abatement was removed, and the income tax rates lowered to compensate for the consequent increase in Taxable Income - hence very little change in the amount of Income Tax payable. HOWEVER, this also meant that the RFR was increased, along with every charge calculated on it - like the cotisation!