Since the start of the Israel-Hamas war, followers of events known for being fashion spectacles — the Oscars, the Met Gala, Eurovision — have watched them become venues for making sartorial as well as political statements about the conflict.

The Cannes Festival in France has not been immune to this trend. Several attendees have used the red carpet on the Croisette to show their support for Israelis or Palestinians during the film festival, with some wearing sashes saying “bring them home,” referring to Israeli hostages taken by Hamas, and others wearing red pins calling for a cease-fire in Gaza.

Off the carpet, the model Bella Hadid ate ice cream near the beach in Cannes wearing a dress made of the material used for kaffiyehs, the scarves long seen as a symbol of Palestinians solidarity and identity.

But those obvious displays have not generated as much buzz as the dress that the actress Cate Blanchett wore on Monday to the premiere of “The Apprentice,” a docudrama about the early life of former President Donald J. Trump.

At first glance the gown — a piece from the designer Haider Ackermann’s one-off spring 2023 couture collection for Jean Paul Gaultier — looked like a simple black dress worn with a pearl necklace across the length of Ms. Blanchett’s bare shoulders.

But as she began to walk the carpet, flashes of other colors emerged: The back of the dress was a pink so pale that it appeared white, and the gown had an emerald green interior lining that Ms. Blanchett repeatedly revealed by lifting its train. The dress had been significantly altered since it appeared on the runway, where it had a knee-length hemline, a lime-green back and a lavender lining.