Self-employed professionals and company heads, whether salaried or not, form a uniform socio-economic group regardless of their legal status with regard to social security and tax legislation. Yet their professional incomes diverge in keeping with this status, making them hard to compare with the incomes of wage earners who are not company heads. Their earned income sometimes remunerates the work of home-help spouses and associates. Some of their business earnings also take the form of unearned income. Their households are, probably more than others, a cohesive entity where individual professional incomes are often impossible to separate, contrary to those of wage-earning partners. A number of tax income indicators are therefore required to compare the incomes of self-employed professionals and company heads with «fully fledged» employees. These indicators range from the individually declared gross earned income to the net income per consumer unit of each household member. Self-employed professionals and company heads have a much wider range of incomes. Their average gross taxable incomes are generally higher than those of employees with the same level of qualifications. However, family and tax redistribution phenomena greatly reduce the deviation in net tax incomes per consumer unit. An individual's self-employed or employee status affects his income level much less than the personal assets he has. The return on the professional experience of self-employed professionals and company heads only continues to grow at later ages with the support of unearned income. This is because, unlike employees, their earned income levels out once they are past their forties. A greater value is placed on higher education qualifications in a self-employed profession, especially post-graduate qualifications and paramedical and social qualifications. However, inheriting a non-employee status from a father does not procure any particular advantage in terms of income. The gaps ...