EU leaders Ursula von der Leyen and Charles Michel will face MEPs on Tuesday over a major gaffe during a visit to Turkey.
Footage of their meeting with Recep Tayyip Erdogan showed Michel and Turkey's president take the two top seats.
Von der Leyen, who is Michel's equal, looked awkwardly for a seat before retiring to a nearby sofa.
Neither European Council chief Michel nor Erdogan offered up their seats to von der Leyen, who is the European Commission's first female president.
A petition gathered by women’s organisations is now calling on Michel to resign, accusing him of having a “thoughtless attitude detrimental to the EU".
“By ostensibly taking leadership as a man over a woman who is your political equal, you offer reinforcement to the dictator on the crush he wants to impose on the women and girls of Turkey, fifteen days after the authoritarian decision that he took to violate gender equality, implicitly authorizing all violence against women and children in Turkey," the letter also states, referencing the Turkish government’s decision to leave the Istanbul Convention, a treaty aimed at tackling domestic violence.
Michel has since apologised, saying he made a mistake but didn’t want to cause further controversy by acting at the moment.
In an interview with Belgian broadcaster LN24 last week, he said “I deeply regret this situation.”
“I can tell you that I have rewound the scene in my head… I would like so much to rewind, to go back. If I could do it, I would make sure that there is no ambiguity whatsoever,” he said.
The event has tarnished the EU’s reputation as a union that has been trying to push gender equality, particularly in Turkey where women’s rights are in decline.
EU law expert Alberto Almanno said instead of Erdogan being lectured about his shameful record on human rights, the episode turned out to be a “major diplomatic win” for him.
“There's no doubt this is a major diplomatic win for Erdogan. I don't think it was 100 per cent deliberate," said Almanno.