Like previous seasons, the series - which involves sex, intrigue and at least one dead body - follows guests and staff at a luxury hotel chain.
This time, the focus is on two hotels, one in Saint-Tropez and one in Cannes.
HBO declined to say whether this year's film festival, which runs from May 12 to 23, will be used as a filming location, Deadline writes.
Swedish Frida Gustavsson and Norwegian Tobias Santelmann are in the cast alongside stars such as Helena Bonham Carter, Vincent Cassel, Steve Coogan, Chris Messina, Chloe Bennet and Sandra Bernhard.
