Some Catholic groups and French bishops have condemned what they saw as "scenes of derision and mockery of Christianity" in Friday's parade choreographed by Thomas Jolly, a leading theatre director.
Criticism has focused on a scene involving dancers, drag queens and a DJ in poses that recalled depictions of the Last Supper, the final meal Jesus is said to have taken with his apostles.
"Clearly there was never an intention to show disrespect to any religious group," Paris 2024 spokeswoman Anne Descamps told reporters on Sunday.
"If people have taken any offence, we are of course really, really sorry," she added.
Jolly, 42, denied taking inspiration from the Last Supper in his nearly four-hour production, which took place in driving rain along the River Seine, the first time a Summer Olympics has opened outside of the main athletics stadium.
The scene, intended to promote tolerance of different sexual and gender identities, also featured French actor Philippe Katerine, who appeared on a silver serving dish, almost naked and painted blue.
He was meant to be Dionysus, the Greek god of wine and pleasure, who was father of Sequana, the goddess of the River Seine.
"The idea was to do a big pagan party linked to the gods of Olympus," Jolly told the BFM channel.
"You'll never find in my work any desire to mock or denigrate anyone. I wanted a ceremony that brings people together, that reconciles, but also a ceremony that affirms our Republican values of liberty, equality and fraternity," he added.
'Great joy'
"I have the impression of floating on a cloud of tolerance, love and shared joy. That was the objective of the ceremony," he added.
Social media sleuths meanwhile suggested the sequence was inspired by the painting "The Feast of the Gods", by the 17th century Dutch master Jan Harmensz van Bijlert.
Performer Katerine also brushed off the controversy, telling BFM "if there was no polemic it would not be fun, if everyone agreed it would be so boring on this earth!"
But he added: "I found his idea of inclusion very good. We are not going to choose exclusion, that would be horrible... it was to be honest a great joy."
Wading into a tense political climate after snap legislative elections this month that left the country in political stalemate, the French extreme and far right have lambasted the show as a distortion of French values.
A spokesman for France's far-right National Rally party, Julien Odoul, called the ceremony "a ransacking of French culture".
In Moscow, Russian foreign ministry spokeswoman Maria Zakharova called it a "giant gay parade".
"If our work is used... to again sow division and hatred.. it would be a great shame," said Jolly.
French drag queen and rapper Piche who also appeared at the ceremony, told BFM there "was nothing obscene or any provocation" in the acts.
'Last minute decisions'
In one of the other striking moments of the ceremony, a woman holding a bloodied severed head and intended to be executed French queen Marie-Antoinette appeared in a window of the Conciergerie -- a building where she was imprisoned after the 1789 French Revolution.
She was later guillotined along with her husband Louis XVI.
While praising elements of the ceremony, French hard-left figurehead Jean-Luc Melenchon criticised this part saying "the death penalty and the execution of Marie Antoinette are from an age of punishments that we do not want to see again."
"Certainly we were not glorifying this instrument of death which is the guillotine," Jolly responded.
A poll by the survey group Harris, which was commissioned by Paris 2024 organisers, showed that 86 percent of respondents in France held positive views on the ceremony.
Quebec-born singer Celine Dion, who brought the curtain down with a solo performance from the Eiffel Tower, emerged as the most notable feature of the parade when respondents were asked what they remembered.
American superstar Lady Gaga also performed an opening number inspired by French music hall. Jolly confirmed it had been pre-recorded, adding "that this was one of the last minute decisions" taken due to the rain as "it could have been dangerous, the ground was slippery".
French President Emmanuel Macron said Saturday that the ceremony had "made our compatriots extremely proud".
