The Oscar-nominated actor was seen hanging out with the "American Oxygen" singer at the Arc club in the City of Light in the early morning hours of Sunday.
Rihanna, 27, is currently in Paris to film Valerian and the City of a Thousand Planets alongside her BFF Cara Delevingne, who also joined the singer at the club. DiCaprio, meanwhile, is in the middle of a European press tour for The Revenant.
A source tells PEOPLE that DiCaprio and Rihanna are "just friends."
"She came by with Cara and said hi," says the source, adding that Rihanna and Delevingne left the club together.
This isn't the first time the two stars have hung out together. In February of last year, DiCaprio was on-hand to help Rihanna ring in her 27th birthday in Los Angeles.
At the time, a source told PEOPLE that while the pair didn't act like a couple, they were flirtatious.
"They would flirt and dance so definitely a little magic there," the onlooker revealed. "They were definitely flirty and dancing, but not over the top."
DiCaprio, 41, and Rihanna later partied with Drake at an N.Y.C. nightclub in May.
VIDEO: Leo and Kate Reunite at the Golden Globes!
The Revenant star was dating model Kelly Rohrbach until just a few months ago.
The pair had only begun dating over the summer and were last spotted together for Thanksgiving before amicably breaking it off.
"They are both so busy and he's got a big movie coming out and she's one of the biggest supermodels in the world," a source previously told PEOPLE. "There is no other person in the picture."
Rihanna has been linked to rapper Travis Scott since the summer and announced in November that he will join her on tour starting in February.
Reporting by LIZ MCNEIL