Lehmann, working as a pundit for Germany's Sky television, could not hide his pleasure at seeing City drop into the Europa League as Napoli joined Bayern in qualification from Group A of the competition.
"Man City play very, very boring football," he said. "They just make their opponents fall asleep with lots of possession.
"But to be honest, that is not tactically very demanding. The way they play here is the way any amateur team plays, only not on such good grass.
"They just pack men behind the ball, have five against two and just move the ball around. The goal then just comes from a fortunate circumstance."
Lehmann, who played in the Champions League final for Arsenal against Barcelona in 2006, albeit for only 18 minutes before being sent off, was also unimpressed by the atmosphere at the Etihad Stadium.
"There was no life in the stadium," he said. "It was dead. The fans are so quiet. You have got to say, though, that they have not got anything really to get excited about here.
"They had possession all of the time, albeit in their own half where nothing was happening.
"It is a shame because it is not typical English football. Napoli have heart and passion and I liked them. It is good that they have gone through.
"We don't want to see Manchester City in the Champions League."