"He's a really good guy," the Marseille goalkeeper said of the 36-year-old Evra, who parted ways with the club after being banned from European football until June 30, 2018.
"I'm very disappointed for Pat, a true friend and a real good guy. We have lost a leader," said Mandanda of the former France captain who also played 379 times for Manchester United.
Evra had been widely condemned for the assault on a Marseille fan which took place ahead of a Europa League tie at Portuguese side Vitoria Guimaraes last week.
And Mandanda acknowledged his former team-mate had made a major error.
"As a professional you need to set an example and this is not the kind of thing you can do," he said. "But he's only human and the circumstances shouldn't have been like they were either."
At the match in question a group of fans had come to the pitchside to harangue the player.
France coach Didier Deschamps described Evra's sanction as heavy on Friday.
"I'm neither condemning him nor judging him," said Deschamps, for whom Evra played at Monaco and with France.
"But it's something that you just can't do and he knows that."
Marseille president Jacques-Henri Eyraud said Friday that it was a sombre day for the 1993 European champions.
"Today, there is sadness, firstly for Patrice Evra, who obviously understood the consequences of his actions and who will no longer be able to display his passion at Marseille," said Eyraud.
"Then, for the supporters of Marseille, who are stigmatised because of the irresponsible behaviour of a handful of them."
In contrast to how Evra is remembered in Manchester, in France there has been a whiff of sulphur to Evra's reputation since a players' strike at the 2010 World Cup in South Africa whilst he was captain.