"Paris was great. She bid on many things, and Leo did, too," a source tells PEOPLE

By Jacqueline Andriakos
Updated May 19, 2015 11:10 AM
Credit: David Silpa/UPI/Landov (Right image)

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The actor, 40, and the heiress, 34, engaged in some haute haggling Monday evening at the Heart Fund’s Generous People Dinner Gala when they both bid on a pricey Chanel purse at the InterContinental Carlton Cannes.

A source tells PEOPLE that the Wolf of Wall Street star was indeed the victor after the friendly bidding war and walked away with the designer handbag, which was reportedly worth more than $10,000. (What a steal.)

The sweetest part? DiCaprio snagged the bag for his mom, Irmelin.

But Hilton was anything but a sore loser. The generous duo stayed for the entire event, catching speeches, a musical performance by hip-hop artist Mos Def, a decadent dinner spread and all of the auctions.

“Paris was great. She bid on many things, and Leo did too,” the source says. “Both her and Leo were so active during the entire auction. It was really nice to see.”

Sporting a suit and his signature scruff, DiCaprio “was laughing and enjoying himself with his friends,” the onlooker says.

The bash at Nikki Beach attracted R&B singer Akon, Victoria’s Secret angel Sara Sampaio, former pro hockey player Anson Carter and others, and raised a record 5.1 million euros in one night for the Heart Fund. The proceeds will be used to provide cardiovascular disease-related screenings and surgeries to young children in remote areas of the world.

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For all of the behind-the-scenes gossip and coverage, head over to PEOPLE’s Cannes blog!