France, Nov. 19 -- Published on Tuesday, the Insee study shows the wealthiest households now earn 31 times more than average families, up from 21 times in 2003. It defines very high incomes by counting all taxable earnings and social benefits, minus direct taxes, then adjusting for household size.

Around 40,000 households qualify as "very high income", earning more than €463,000 annually. Nearly half live in the Paris region, and 82 percent are married or in civil partnerships.

Their wealth comes not just from salaries or pensions but from profits on professional activity such as farmland, rental income and financial assets including shares, business stakes, life insurance and investment contracts.

The gap between rich and poor h...