The official poster for this year’s Cannes film festival has been criticised after Italian actor Claudia Cardinale appeared to have been airbrushed to make her look thinner.

French media poured scorn on the festival for seemingly tampering with a photograph of Cardinale swirling her skirt on a Rome roof in 1959.

“Claudia Cardinale dropped a dress size in one swirl,” said the left-leaning Libération, while the culture magazine Télérama questioned why it was necessary to retouch the star. Le Monde offered a slide tool for readers to analyse how the image had been changed.

“While the poster is magnificent, the photograph has clearly and deplorably been airbrushed to thin the actress’s thighs. What a pity,” it said. There was a similarly hostile reaction on social media, with one Twitter user saying: “If even Claudia Cardinale cannot represent beauty without being retouched, we really are in trouble.”

Others spoke of the “dictatorship of thinness” or pointed out that “Cardinale wasn’t thin enough for Cannes”.

However, the actress, now 78, was unimpressed by what she called a “fake row”. She told the Huffington Post: “This image has been retouched to accentuate this effect of lightness and transpose me into a dream character.

“This concern for realism has no place here and, as a committed feminist, I see no affront to the female body. There are many more important things to discuss in our world. It’s only cinema.”

Cardinale said in a statement released by the festival that she was honoured to feature on the poster for its 70th anniversary year. “That dance on a roof in Rome … reminds me of a time when I could never have imagined climbing up the red-carpeted steps of the most celebrated” film festival in the world, she said.

But Claire Serre-Combe, of the French women’s group Osez le feminisme! (Dare to be Feminist), said it was a scandal that Cardinale who was “thin and magnificent in the original photo”, should have to “lose kilos” for the poster.

The festival’s director Thierry Fremaux told AFP the poster had been “very well received”.

Tunisian-born Cardinale starred in some of the greatest European films of the 1960s and 1970s including Federico Fellini’s 8½ and Luchino Visconti’s The Leopard.