Eighty-two actresses, filmmakers and producers marched arm and arm to demand equality and "a safe workplace", seven months after the world was shaken by the #MeToo movement and the fall of mogul Harvey Weinstein.
The ranks included a battalion of Oscar winners from Helen Mirren and Marion Cotillard to US blockbuster directors Ava DuVernay and Patty Jenkins who made "Wonder Woman".
"We demand that our workplaces are diverse and equitable so they can best reflect the world in which we live," said Blanchett in a statement read out with the legendary 89-year-old French director Agnes Varda.
Blanchett, a double Oscar winner, said they wanted "a world that allows all of us in front and behind the camera to thrive shoulder to shoulder with our male colleagues."
With Cannes under fire for its dearth of women directors, the world's top film festival hoped to fend off some of the fierce criticism with the march.
The number of protesters was highly symbolic as it represented the 82 films by female directors who have competed for the top Palme d'Or prize since 1946 -- a number dwarfed by the nearly 1,700 male contenders.
The star-studded group stopped halfway up the stairs to the Palais des Festivals to mark the obstacles they face in trying to reach the top.
