Marseille twice took the lead against the reigning champions at Stade Velodrome, only to ultimately suffer a loss that leaves them five points behind table-topping PSG.
Ayew was sent off after the final whistle for protesting to the referee.
"I told him that we were fed up and I received a second yellow card," he told reporters.
"As we are now not allowed to speak to the referees anymore and to tell them anything, that's how it works.
"The staff of the team went to see him. He said to them that I didn't say anything bad. It is just that I came too close to him. That's not good for the 'image' apparently. So I got another yellow card."
Ayew continued: "[PSG midfielder Blaise] Matuidi made several fouls during different times of the game. At the fourth one, the referee gave him just a warning.
"For us, the first foul after 10 minutes [saw Alaixys Romao booked]. Why it was, I do not know.
"We are not going to spend more time talking about it. It's been happening for a while, it works this way for Marseille.
"We have to forget about it and just play football."
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