Ivorian midfielder Toure, 35, has left City after eight successful seasons, the last of which he spent reunited with a boss from his Nou Camp days as the Manchester club swept to Premier League glory.
But Toure barely featured under Guardiola, who allowed him to leave Barca in 2010, and he was handed only one start across the whole league campaign as City won 100 points and scored 106 goals.
Guardiola’s handling of Toure’s send-off has also disappointed the player, who compared his exit to those of Andres Iniesta and Gianluigi Buffon, who departed Barca and Juventus to much fanfare.
In an interview with France Football, Toure suggested that the City head coach might have treated him less favourably because he is African.
He said of Guardiola: “He was cruel with me. Do you believe that Barcelona could have done that with [Andres] Iniesta?
I even started wondering to myself whether it was about my colour.
“I’m not the first person to talk about his different ways of treating people. I know some other people at Barca who have also wondered about that.
“Maybe it’s the case that we Africans aren’t always treated by certain people in the same way that they treat others.
“When you see that he’s had problems with Africans wherever he’s been in the past, you wonder.
When the day comes that he picks a team featuring five Africans — and not naturalised Africans — I promise I will send him a cake!
Toure, who won three Premier League titles, the FA Cup and two League Cups with City, added of the 47-year-old former Bayern Munich manager: “Pep likes to dominate and wants to have his obedient players kissing his hands. I don’t like that kind of relationship. I respect my coach but that’s not for me. He took away my chance to say goodbye to City, a club with wonderful fans. I would have liked to leave in the same way that Iniesta and [Gianluigi] Buffon did, but Pep stopped that.”
Toure is now a free agent and has been linked to ambitious French club Marseille.
Meanwhile Liverpool have been fined €20,000 for disturbances at the Champions League quarter-final first leg in April, which included an attack on the Man City bus.
City’s bus was pelted with bottles and cans ahead of the match, which Liverpool won 3-0, and the visitors had to find a replacement for the return trip to Manchester after a window was smashed.
The Reds, runners-up in the tournament as Real Madrid won a 13th title in Kiev last month, condemned the behaviour as “completely unacceptable” in the immediate aftermath.
City boss Guardiola has also been suspended by Uefa for one match for his dismissal in the second leg of the tie, with a further match ban suspended for one season.
Liverpool were also fined €9,000 for setting off fireworks in the second leg with City and the second leg of the semi-final at Roma.
Guardiola was disciplined by Uefa after his dismissal in the 2-1 second-leg loss, after which the City boss questioned the decision-making of referee Antonio Mateu Lahoz.
European football’s governing body published the disciplinary verdicts for cases heard on May 31, with one involving a Russia 2018 World Cup host city.
Zenit St Petersburg were fined a total of €70,000 for offences at the Europa League last-16 tie with Red Bull Leipzig.
A €50,000 fine was imposed on Zenit for “the racist behaviour of its supporters”, Uefa said, with the club ordered to play their next home game in Europe behind closed doors.