The 38-year-old, who signed a contract with the Franconians on Thursday, will assume responsibility of the first team with immediate effect.
The French-born former defender first arrived in Germany in 2003 when he joined Werder Bremen, going on to win the league and Cup double with the Green-Whites in 2004. He repeated that feat two years later with FC Bayern München, before signing for Hannover 96 in 2008. Ismael hung up his boots for good in 2009 after being plagued with a persistent knee injury.
His new position at der Club is his third as a coach, after he previously took charge of Hannover’s reserve side at the end of 2011 and filled the same role at VfL Wolfsburg from summer 2013 onwards. Last season he guided the Wolves' second team to glory in the Northern Regional League, narrowly missing out on promotion to the third division via the play-offs.