Petit believed that Henry would have to humble himself if he was to succeed as a manager.
Henry endured a short and miserable stint with the Ligue 1 club, finding himself sacked after a few months and replaced by the man whose job he took in the first place.
Petit told Paddy Power Magazine of Henry: "Thierry was a tremendous player.
"Everyone knows what he has done on the pitch. Now he wants to be a manager and his first job at Monaco did not go well – I think he is still a player in his mind.
"You have to change the mentality – you can't keep the player's mindset if you want to be a manager.
"The way you talk to players and control training sessions is very important. Even if it's your first job, footballers will test you constantly.
"As a player, Thierry was terrific and I hope he achieves the same as a manager. But I remember saying something to him at ArsenaI.
"I told him, 'Every time you score a goal, you should be more humble and try to have a connection with the fans, rather than living in your own world'. He didn't like it."