 Bossis spent much of his time at right back during Nantes' championship-winning seasons in 1977 and 1980, in which Thierry Tusseau normally started on the left, but made the left back position his own beginning in 1981.Bossis helped Nantes to finish first or second in every season between 1976 and 1981.The club added a third title in 1983, finishing ten points ahead of second-place Girondins Bordeaux.