BOSS reverses course: CSE-paid mutuelle share now in montant net social

The montant net social is the aggregate that beneficiaries of the revenu de solidarité active (RSA) and the prime d'activité declare in their quarterly resource statements to calculate benefits. Employers report it through the déclaration sociale nominative (DSN) and display it on payslips, where it is a mandatory mention. It is built from all gross amounts of remuneration and replacement income paid by the employer, minus the social contributions and charges payable by the employee.

Within that computation, the treatment of compulsory health cover follows a fixed split. The employer's contribution to the complémentaire santé required by Article L. 911-7 of the Code de la sécurité sociale, covering frais de santé from illness, maternity or accident, is included in the montant net social, while the mandatory employee share of that same cover is deducted. The same inclusion/deduction split applies to the collective guarantees of Article L. 911-1: the employer's funding share is included and the employee's funding share is deducted. Other benefits in kind or in cash that are socially and fiscally exempt and linked to social activities, including CSE social and cultural activities, remain outside the aggregate.

Question 30 of the Bulletin Officiel de la Sécurité Sociale (BOSS) page on the montant net social addresses the specific case where the comité social et économique (CSE) pays part of the employee's mandatory contribution financing the frais de santé guarantees, the employee's mutuelle.Boss The previous answer treated that CSE payment as one of the exempt CSE social-activity benefitsBoss: it stated that the CSE's share must not be taken into account in the montant net socialBoss. The page updated on 28 October 2026Boss reverses that answer: where the CSE pays part of the mandatory employee contribution for the frais de santé guarantees, that CSE share must now be taken into account in the montant net socialBoss.

The reversal changes the payslip and DSN figure for every affected employee. Compared with the prior position, which excluded the CSE-paid portion entirely, the montant net social for those employees now includes itBoss, so the declared and displayed amount rises by that portion. Nothing in the revised answer changes the ordinary deduction of the part of the mandatory employee contribution the employee still pays personally, nor the inclusion of the employer's own contribution.

Payroll teams should identify employers where a CSE funds part of the compulsory employee mutuelle contribution, adjust the calculation parameters so the montant net social reported through both the payslip display and the DSN declaration reflects the revised computation. Because the montant net social feeds employees' social-benefit declarations, an understated figure exposes employees to incorrect benefit calculations and employers to declaration corrections. Legal basis: Code du travail, Article R. 3243-1 (9 bis), with calculation rules in the arrêté du 31 janvier 2023, as interpreted by BOSS, Montant net social, question 30, updated 28 October 2026.