The law, aimed at stopping animal abuse in circuses, was passed by the city council Monday but is still awaiting signature from leftist Mayor Miguel Angel Mancera.
Circus performers are appalled that the new rule slaps a blanket ban on the use of animals in shows -- a rule they said would harm and in some cases end their jobs -- instead of creating an inspection system.
And oddly, they said, the law does not ban animals in other public shows such as bullfights.
"We have already demonstrated that we do not harm our animals. They are part of our family!" said Isaid Berti, an animal trainer, weeping.
Berti, a fifth generation performer in a circus now working in Monterrey, said, "we have watched these animals be born and take care of them their whole lives. How would we abuse them?"
Berti, 27, acknowledged that animal abuse does happen in some circuses.
"So why should those who have done no wrong pay the price for those who have?" He suggested an inspection system for the massive city's estimated 50 circuses.
Most of Mexico does allow animals in circuses, but five states currently ban them, in addition to Mexico City's planned prohibition.