A thigh injury in pre-season training meant Bocaly did not return to action until 1 September 2012 against Sochaux. He was in the starting eleven for Montpellier's debut in Champions League football, a 2–1 loss at home to Arsenal in the group stage, and was voted man of the match on his next league appearance, a 2–0 win away to Nancy in which the defence were returning to last season's form. Four days later, Bocaly was sent off for a foul that gave away a penalty and left Schalke's Julian Draxler with a broken arm; his team drew the game to earn their first Champions League point. He was again sent off at the end of October for a professional foul on Nice's Neal Maupay in what was Montpellier's first home win of the season.