In France each resident over the age of 18 has to make an annual tax return even if they have no income.
The French tax return is made annually to 31 December and must be submitted by the end of the following May.
The French tax return is declared and tax calculated based on the household in total.
In the UK you must make a tax return if one is issued to you and must request a tax return for submission if you have a source of taxable income not known to the Inland Revenue.
The UK tax return is made annually to 5 April and must be submitted by the end of the following January.