France: 35% of net income, insurance included
France applies the bluntest ceiling of any country here, a single binding percentage, and it is written against take-home pay. The Haut Conseil de stabilité financière caps the taux d'effort, total loan payments as a share of income, at 35% of net income, with a maximum loan term of 25 years. A French borrower on 4,000 euros net has a very different ratio from one entering 4,000 euros gross, and the 35% HCSF cap is written against the net figure.
Two details make the French limit bite harder than the number suggests. The 35% includes the assurance emprunteur, the borrower's insurance that is effectively compulsory on a French mortgage and can add a meaningful amount to the monthly cost, so the payment being measured is larger than the loan's own repayment. And the cap applies to all loan repayments together, not to the mortgage alone: a car loan or a consumer credit eats directly into the same 35%.
The rule is binding rather than advisory, but not absolute. Banks may breach it on up to 20% of their quarterly lending, a flexibility mostly directed at first-time buyers and owner-occupiers.
Worked example: €4,000 net a month
The ceiling is 35% of €4,000, or €1,400 a month for every loan payment combined, insurance included. An existing €250 car loan leaves €1,150 for the mortgage and its insurance, and the 25-year term limit caps how far that payment can be stretched to buy a larger loan.