the amount of tax is calculated by multiplying the cadastral income of each property by the rates voted by each beneficiary local authority for the year in question for residential premises used as the taxpayers main home compulsory relief for dependents or optional relief general relief on the base special relief on the base relief for disabled people is deducted from the notional rental value the amount of tax is calculated by multiplying the income from the tax base by the rates voted by each beneficiary commune or public establishment for intercommunal cooperation for the year in question