Patrice Evra has accused Carlos Tevez of lacking respect after he was pictured holding up a banner mocking Sir Alex Ferguson.
Tevez has refused to apologise for brandishing a placard saying 'RIP Fergie' during Monday's parade to celebrate Manchester City's Premier League title success.
The move has stunned Tevez's old allies at his former club Manchester United, with Evra distinctly unimpressed by the Argentinian's actions.
Evra told The Sun on Sunday: "I was very surprised by Tevez's attitude against Sir Alex Ferguson.
"I'm not sure how the manager feels about it but I'm sure he won't be impressed.
"It's disrespectful. Tevez spent two years at this club and was treated extremely well by the manager so I don't really understand his reaction or the truth about the situation."
Although City were quick to apologise for the 28-year-old's behaviour, Tevez himself remained unrepentant when he landed in South America just days later.
It is not the first time there has been tension between the Manchester rivals over Tevez, who swapped clubs in 2009.
Evra believes City were also culpable in putting up a huge poster with the message 'Welcome to Manchester' when Tevez joined the club from their cross-city rivals.
The France international left-back added: "The poster was in very bad taste, no one from Manchester United appreciated it.
"Tevez is an adult, he plays for another club and is responsible for his own actions.
"It's a shame because he was always respected at Manchester United and remained in contact with some of the players. But I have no idea what will happen now."
Evra is still trying to get over the heartache of losing the title to City in the final moments of the last day of the season but he insists United will emerge far stronger for the experience.
The 31-year-old added: "It left a bad taste because we lost the title in the last minutes of the final game.
"But this will make us stronger and more determined to reclaim the title next season.
"City will probably argue that they won both derby games and so deserve to be champions. But over the course of the campaign there wasn't a great deal of difference between the two sides.
"A season without a title for Manchester United is extremely rare so we have to use this as a positive next season."