The actor, 51, and the model, 31, were seen together in the French capital on Monday in photographs published by Page Six, with both wearing thin matching rings on their left hands.
The publication reported it had contacted representatives for Cooper and Hadid for comment.
The sighting came after Cooper was photographed heading to the gym alone two days earlier without a ring.
Cooper and Hadid , who have been together since October 2023, have largely kept their relationship out of the spotlight despite increasing public interest.
They were most recently seen together in July while attending the wedding of Taylor Swift and Travis Kelce at Madison Square Garden.
Cooper, best known for The Hangover trilogy, A Star Is Born and his Oscar-nominated film Maestro, made a surprise appearance in support of Hadid at this year's Met Gala but did not walk the red carpet.
Hadid , meanwhile, continues to balance her fashion career with family life and recently shared photographs from the couple's holiday in Paris on social media.
Their latest appearance comes more than two years after they were first linked, when they were spotted leaving a dinner date together in New York in October 2023.
Despite the ongoing interest in their relationship, the pair have generally kept their private lives away from public view, making only occasional public appearances together.
