A photo posted on Instagram by Lauren Santo Domingo, a founder of a fashion website, showed the former first daughter at the fundraiser along with Huma Abedin, Clinton's vice chairwoman for the presidential campaign, and actress Dakota Fanning.
The caption for the photo read: "Hillblazing at home in paris #imwithher."
Derek Blasberg, a Vanity Fair editor and writer, also posted a photo on Instagram showing Barbara Bush at the official Clinton event, which was hosted by Vogue's editor-in-chief, Anna Wintour.
Tickets to attend the fundraiser ranged from $500 to $10,000, according to Clinton's campaign website.
If Barbara Bush, one of the former Republican president's two twin daughters, is supporting the Democratic presidential candidate, she would reportedly be following in the footsteps of her grandfather, President George H.W. Bush.
CNN reported that aides for the Clinton campaign and a spokesperson for the former president Bush did not respond to requests for comment.
While George W. Bush has yet to endorse a candidate, his wife, Laura, has made references alluding to her willingness to consider Clinton over Trump.
Former Florida Governor and Republican presidential candidate Jeb Bush has opted to vote for neither candidate. In an interview with MSNBC in July, Jeb Bush said, "I can't vote for Hillary Clinton, and I can't vote for Donald Trump and it breaks my heart."