The NY Post also reported the pair were seen around the Hotel du Cap Eden Roc, in the resort town of Antibes, in the south of France.
"They walked around the grounds together," a source told the newspaper.
"It looked like they were a couple."
Lively had reportedly auditioned for a role in Luhrmann's upcoming The Great Gatsby, which ultimately went to Carey Mulligan.
Meanwhile, Refaeli has been causing a stir of her own in the nearby town of Cannes, making a stunning appearance on the red carpet at the famed film festival.
The 25-year-old, who had been dating DiCaprio on-and-off for five years, split from the star earlier this month.
Leonardo Dicaprio and Blake Lively
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