European Commission chief Ursula von der Leyen found herself relegated to sofa when Mr Michel jumped in the only chair available next to Turkish President Tayyip Erdogan at talks in Ankara. Ms von der Leyen expressed surprise and raised a hand in disbelief in the bizarre episode which was caught on camera.
Mr Michel has now spoken of his embarrassment.
He said: “I make no secret of the fact that I haven’t slept well at night since because the scenes keep replaying in my head.
“If it were possible I would go back and fix it.”
Footage from their meeting on Tuesday showed the first female head of the EU executive, the only woman in the talks, gesturing in disbelief and uttering a surprised sigh as Mr Erdogan and Mr Michel took the two centre-stage seats prepared, relegating her to an adjacent sofa.
Her spokesman Eric Mamer said: “The president of the Commission was clearly surprised.
“She should have been seated in exactly the same manner as the president of the European Council and the Turkish president.”
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In a Facebook post on the following day, Mr Michel said the incident was “regrettable” and caused by “Turkish authorities’s strict interpretation of protocol rules.”
But he said he decided against a public confrontation.
While the Commission conveyed Ms von der Leyen’s irritation, an EU official who declined to be named said doing so might have provoked a “protocol and political incident.”
He said: “Turkey meant no disrespect.
“It extended a very courteous welcome to both presidents and strictly adhered to international protocol.”
He said: “Turkey is a deep-rooted state, it is not the first time it hosts a guest. The protocol followed for meetings in Turkey is within the international protocol framework. The same was done here too.
“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 suggestions.”
Ties between Brussels and Ankara have been strained since a failed coup in 2016 prompted a crackdown in Turkey that has led to the arrests of thousands.
A maritime row between Turkey and Greece stoked tensions last year and the EU threatened sanctions on Ankara, but they are now testing a cautious thawing of relations.