As PEOPLE broke the news that the couple have separated, the Wall Street Oscar winner was in France, where he was spotted having dinner with friends at La Petite Maison in Nice on Tuesday night.
A source tells PEOPLE that the 68-year-old has been spending time in the South of France with his billionaire friend Jean Pigozzi, but will be flying out in a couple of days to attend the Deauville Film Festival in northern France.
Douglas's biopic of showman Liberace, Behind the Candelabra, is set to open the festival on Friday night.
Being back in Deauville will be a poignant reminder for the star of how his love affair with Zeta-Jones, 43, began – the pair were introduced to each other at the event in August 1998.
When Douglas set eyes on the dark-haired Welsh beauty he reportedly told her he wanted to father her children.
The couple, who share the same birthday, wed two years later at the Plaza Hotel in New York and went on to have two children – Dylan, 13, and Carys, 10.
"Catherine and Michael are taking some time apart to evaluate and work on their marriage. There will be no further comment," reps for the couple said in a statement. Another source tells PEOPLE the pair, who haven't been photographed together in more than four months, are "taking a break" but neither has filed for divorce or moved toward a legal separation.