It's possible to make out Prince Mohammed saying "Don't worry", to which the French President responds "I am worried".
British Prime Minister Theresa May, speaking to Sky News before the summit, said she would press both on Yemen and Khashoggi, a Washington Post contributor who was killed when visiting the Saudi Arabian consulate in Istanbul.
In contrast, Mr Putin and the crown prince shared a smiley, enthusiastic greeting at the gathering.
Saudi Crown Prince Mohammed bin Salman and Putin clasped each other's hands and smiled widely as they greeted each other Friday.
The two leaders, who are in Argentina for the G20 summit, met in the prince's residence in Buenos Aires and discussed Saudi Arabia's readiness to supply India with oil and petroleum products. But it received wide traction on social media, with Macron telling the prince, "You never listen to me", to which Prince Mohammed replies, "I will listen, of course".
Macron, undeterred and continuing on with the conversation, later says, "I'm a man of my word". Saudi Arabia claims that the prince had no prior knowledge of the murder.
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It says Mr Macron told MBS that Europeans wanted global investigators to take part in the probe on Mr Khashoggi's death and stressed "the necessity of a political solution in Yemen".
But, in an exclamation point-heavy statement before the summit, Trump said it did not matter whether Prince Mohammed knew about Khashoggi's death because Saudi Arabia was important for USA business and for its hostility to Iran.
"The Prime Minister stressed the importance of ensuring that those responsible for the appalling murder of Jamal Khashoggi are held to account, and that Saudi Arabia takes action to build confidence that such a deplorable incident could not happen again", Mrs May's office said in a readout of her meeting with Prince Mohammed.
US President Donald Trump said before the summit in a statement that he was unconcerned with whether Prince Mohammed was involved in Khashoggi's death, naming business ties with Saudi Arabia and its hostility to Iran as his priorities. The two leaders are controversial figures at the summit.
The world will have to wait a little longer for an update on how Trump and Chinese President Xi Jinping are getting on.
White House spokesperson Sarah Sanders insists the reason for the cancellation was the situation with Ukraine, but said the probe into possible collusion between the Trump presidential campaign and Russian Federation was damaging ties between the two countries.More news: Cohen's Trump Tower Lies Were Part Of Mueller's Questions For Trump