The prestigious Cannes festival has come under criticism for failing to showcase more films by women directors.
The protest comes after a period of turmoil in the industry following allegations of sexual harassment.
This is the first Cannes festival since allegations of sexual abuse were first made against producer Harvey Weinstein last year. He has always denied engaging in non-consensual sex.
"We are 82 women, representing the number of female directors who have climbed these stairs since the first edition of the Cannes film festival in 1946. In the same period, 1,688 male directors have climbed these very same stairs," the two-time Oscar winner said.
"The prestigious Palme d'Or has been bestowed upon 71 male directors, too numerous to mention by name, but only two female directors," Ms Blanchett remarked.
The women taking part in the protest included all of the festival's female jury members and many women actors, directors and producers.
'A moment of real heft and resonance'
By Neil Smith, Entertainment reporter at CannesAt an event often more associated with the flashy and superficial, this was a moment of real heft and resonance.
The sight of 82 women walking slowly, silently and purposefully up the red-carpeted stars of Cannes' Grand Theatre Lumiere brought home the shocking under-representation of female film-makers at an event meant to celebrate the totality of world cinema.
The timing was perfect. The evening's film, Girls of the Sun, not only has a female director but also tells of a commando unit of female fighters in Kurdistan.
Some of the 82 were familiar. Many were not. Together, though, they sent out a powerful statement that both this festival and the industry that sustains it would do well to heed.
The French Equality Minister Marlene Schiappa said it had received "several calls" since the gathering began on 9 May.
The allegations of sexual harassment made against well-known male film industry figures has created a public conversation about gender discrimination and sexual harassment in many industries.
It led to the creation of a #MeToo hashtag, giving women an opportunity to share their experiences.
The Time's Up movement was created by more than 300 actresses, writers and directors to help fight sexual harassment in the film industry and other workplaces.
At the Golden Globes in January, many film stars wore black gowns in support of the Time's Up movement, standing in solidarity with victims of sexual assault and harassment.
