It should be noted that the functioning and calculation of taxation in Spain are not the same as in France. Thus, the Spanish income tax does not escape the rule.
IRPF is personal income tax in Spain and it is essential that you declare it along with other tax returns if you are a tax resident in the country. It is a direct, personal, subjective, progressive and periodic tax that accounts for all the income obtained over that year and it applies to every Spanish tax resident.
It is a direct tax because it is charged directly to the taxpayer, personal because it is dependent upon the individual not a product; subjective because it takes into account the physical conditions of the taxpayer; progressive because it is the base tax which is important, it's the tax rate that is high; periodic because it is deducted at regular intervals throughout the year.