The European Commission's first female president, Ursula von der Leyen, has blamed sexism for the "sofagate" snub.
Ursula von der Leyen was denied a chair when meeting Turkish President Tayyip Erdoğan alongside European Council President Charles Michel.
She said that the 'sofagate' incident only happened because she is a woman.
"I cannot find any justification for how I was treated, so I have to conclude that it happened because I am a woman. Would this have happened if I had worn a suit and a tie?" she stated during a speech to the European Parliament on Monday.
Video of the occurrence showed the first female head of the EU executive, and the only woman in the talks, briefly standing and gesturing in amazement at the two men before she sat on a couch adjacent to the main chairs.
"I am the first woman to be president of the European Commission. I am the President of the European Commission. This is how I expected to be treated when visiting Turkey two weeks ago, like a Commission President. But I was not.
"In pictures of previous meetings I did not see any shortage of chairs but then again I did not see any pictures of women neither," she continued
Addressing female MEPs directly, President von der Leyen said: "You know exactly how I felt. I felt hurt, and I felt alone, as a woman and a European.
"It is not about seating arrangements or protocol. This goes to the core of who we are. This goes to the values our Union stands for, and this shows how far we still have to go to before women are treated as equals, always and everywhere."
The first female president acknowledged that she was in a privileged position and could raise her voice as the leader of what she described as a "highly respected" institution.
"As a leader I can speak up and make myself heard. But what about the millions of women who can not? Women who are hurt every day in every corner of our planet, who do not have the power or cannot speak up," she stressed.
It was one of the most impassioned speeches of her tenure.
After the 'sofagate' incident, Turkey blamed the EU for "unjust accusations".
Turkey's Foreign Minister Mevlüt Çavuşoğlu said that the seating arrangement was in line with international protocol and that Turkey was being subject to “unjust accusations”.
“The protocol at the presidency met the demands of the EU side. In other words, the seating arrangement was designed to meet their demands and recommendations,” he added.
The meeting was arranged as an attempt to repair tense EU-Turkey relations.