Receiving 13th month if on maternity leave in December?

Following on from my question regarding accrual of annual leave whilst on maternity leave, does anyone know if I would receive my usual 13th month (prime fin d'annee) if I happen to be on maternity leave during the month of December? I ask because this would be paid by my employer and not mutuelle. I'm thinking that to withold the 13th month would be discriminatary to women who happen to be on maternity leave in December but wanted to check. Thank you.