 -- Three weeks before Election Day, Donald Trump Jr. left the campaign trail and the country to speak at a private dinner in Paris organized by an obscure pro-Russia group that promotes Kremlin foreign policy initiatives and has since nominated Russian President Vladimir Putin for the Nobel Peace Prize.

A key organizer of the event later told reporters she flew to Moscow to brief a senior Russian official about the session.

The White House referred question about the president’s son to the Trump Organization. A spokeswoman for the Trump business did not initially respond to questions from ABC News about why Donald Trump Jr. flew to France for the session during a critical phase of the presidential campaign, who arranged for him to attend, whether he was paid, what was discussed or if anyone vetted the group before he went.

After publication, a Trump Organization spokeswoman told ABC News, “Donald Trump Jr. has been participating in business related speaking engagements for over a decade – discussing a range of topics including sharing his entrepreneurial experiences and offering career specific advice." The Trump Organization declined to respond when asked how much Trump Jr. was paid for his appearance.

At the time, Trump was commanding a speaking fee of “$50,001 and above,” according to his speaker bureau’s website.

The group sponsoring the session, the Center of Political and Foreign Affairs (CPFA), was founded by a wealthy French businessman and his partner, who are reported to have made major investments in Russia.

“They are openly linked with the Russians,” said Renaud Girard, a French opinion writer who served as the moderator of the session Trump attended. “They don’t hide it at all.”

Thirty people joined the Trump scion for the private gathering, on Oct. 11 at the Ritz Hotel, according to Girard.

Trump’s appearance briefly made news after the event, including in a Wall Street Journal report that quoted one of the hosts, Randa Kassis. She told the newspaper she traveled to Moscow shortly after the U.S. election and discussed details of the Trump dinner with Mikhail Bogdanov, the deputy head of Russia’s Foreign Ministry.

Congressional sources told ABC News that Trump’s jaunt to Paris remains one of a number of episodes — some confirmed and others unproved — that have fueled suspicions that there was communication between the Trump team and the Russian government during the closing months of the 2016 presidential campaign.

In France and in Washington diplomatic circles, those familiar with the French think tank circuit told ABC News they had never heard of the CPFA. The organization has no fixed address, and neither of its founders, Fabien Baussart and Kassis, responded to calls and emails seeking an interview.

“I have been dealing with French think tanks and research institutes for 35 years, and I’ve never heard of it,” said Daniel S. Hamilton, the executive director of the Center for Transatlantic Relations at the Johns Hopkins Schools of Advanced International Studies. “That tells you something.”

Marie Mendras, a political scientist in the field of Russian and post-Soviet studies at the Paris School of International Affairs, said she was reluctant to weigh in. “I can only say that Fabien Baussart is known in France for his close Kremlin and Russian business connections,” she said in an email exchange.

No one involved with the CPFA has responded to phone calls or questions. And unlike in the U.S., France does not require nonprofit organizations to make information about their financing publicly available. Hamilton was one of several experts who noted that the Russian government is believed to have spent considerable sums to fuel the European think tank and opinion circuit, though they all explicitly said that they did not know if there was any connection between those Russian activities and the CPFA.

“Money plays a big role here through front organizations,” he said. “But it’s hard to ever know.”

Reports in French newspapers and intelligence journals indicate that Baussart and Kassis have frequently touted their Russian ties. A news report in France described Baussart as “a former lobbyist for Russian oligarchs in France.” A news service called Intelligence Online reported that Baussart organized “efforts to lobby the French authorities and, in particular, the French intelligence services.”

Kassis is described in French news reports as a Syrian-born activist who has sought Russian support for her position on Syria. She has posted photos online showing her in meetings with senior Kremlin officials. Just this week, a report by the English-language Russian website Sputinik News said Kassis was in Geneva and told reporters she was meeting with Russian Deputy Foreign Minister Gennady Gatilov.

Last September, the CPFA attempted to raise its profile by organizing what it described as “peace talks” between Armenia and Azerbaijan, two former Soviet republics with a long-simmering, frozen conflict born out of the collapse of the Soviet Union. Those countries signed a truce in 1994, according to the BBC, but sporadic fighting has persisted.

The organization invited former U.S. diplomat James Rubin, at the time a strong supporter of Hillary Clinton’s, and Paddy Ashdown, a British politician and former diplomat who served as the leader of the Liberal Democrats, to help facilitate the talks. But the weekend was canceled. Rubin instead flew to France and joined the group for one of its salon-style dinners. Rubin declined comment.

Ashdown told ABC News he initially accepted the invitation but then became suspicious of the organizers and backed out.

“It was clearly an attempt to instrumentalize me for their own very dubious purposes. I told them I wasn’t born yesterday and that the Serbs used to try that and didn’t succeed, and they were probably cleverer,” he said in an email. “Result: The engagement was canceled, along with the ‘peace talks.’”

Others who have attended CPFA dinners, Girard said, are former U.N. Secretary General Kofi Annan, and the organization’s website shows a visit from a former head of British intelligence, Richard Dearlove. Neither one replied to emails seeking comment.

One dignitary who spoke to the group told ABC News he was hired through a speaker’s bureau and was paid well in excess of the typical fee — an amount in the tens of thousands of dollars. He asked not to be identified because he did not wish to stoke any ill will with Kassis and Baussart.

Girard said that on the evening Trump attended, the guests included ambassadors to France, lawyers, bankers and business executives. Conversation at the dinner was cordial and covered a range of international affairs. Girard said the gathering occurred at a time when most of the media had dismissed Donald Trump Sr.’s chances of winning the U.S. election as highly unlikely. “The one thing that amazed me was that [Donald Trump Jr.] was confident that his father would win,” Girard said.

ABC News’ Paul Blake and Cho Park contributed to this report from New York City.

This story was originally published on Mar. 2, 2017 at 12:21 p.m. It has been updated with new information.