Most people are pleasantly surprised to pay less income tax or “impôts sur le revenu” in France than they would as a resident of the UK.
A substantial difference is the “Quotient Familial” better known as the “parts” system. In the UK we are taxed as separate individuals. In France you are taxed together as a household.
Just to be clear, a “couple” in France is defined as two people who are either married or in a “Pacte Civil de Solidarité”, or PACSed. Even children receive an allowance! Co-habiting couples will be therefore taxed as individuals.
Income tax is always applied in arrears, so if you move to France in January in any year, your first tax return is to be completed in May the following year. Anyone who is deemed to be a fiscal resident of France must complete a tax return or “déclaration d’impôts”. It does not matter if you have no income, or if all your income is deemed “exempt”, or where in the world the income is paid; if you live in France you must complete and file a tax return.
Another point is that it is unlikely that you will be sent a tax return in the first instance. The law obliges you to go and obtain one; the argument that you did not receive a return does not protect you from being fined. These can be obtained from www.impots.gouv.fr or from your local tax office.
We find it very common that people fill in the wrong forms, omit important documentation, complete the wrong boxes and end up paying more than they should. This even happens where people have received help from someone at the tax office as certain forms of UK income remain taxable by HMRC and some are taxed here, but all income must be placed on the tax form regardless of where it is derived.
We are not tax advisers and always recommend that you seek help from a professional in order to make sure that your tax affairs are in order from the outset.