More than 600 cinema figures have said the growing influence of the far right on French cinema production risks turning into a “fascist takeover of the collective imagination”.

In an open letter published in the newspaper Libération to coincide with the opening of the Cannes film festival, they said the billionaire Vincent Bolloré’s dominant position in French film production and distribution threatened the independence of the industry.

The actor-director Juliette Binoche, the director and photographer Raymond Depardon and the French-Iranian film-maker Sepideh Farsi were among those who wrote: “By leaving French cinema in the hands of a far-right owner, we risk not only the standardisation of films, but a fascist takeover of the collective imagination.”

Bolloré, a conservative industrialist, has a powerful media empire, including the channel CNews, the radio station Europe 1 and the Sunday paper Le Journal du Dimanche, and is close to figures on the far right. Politicians on the left have attacked CNews for giving a platform to reactionary voices they say have aided the rise of the far right. The Paris prosecutor’s office last month opened a legal investigation into racist comments on the channel against the mayor of Saint-Denis, Bally Bagayoko. The channel denied racism.

Bolloré’s powerful role in the French cultural world is sparking revolt among creatives ahead of next year’s French presidential election. In an unprecedented walkout last month, more than 100 writers quit the publishing house Grasset in protest at Bolloré’s control of its parent company Hachette Livre. “We refuse to be hostages in an ideological war that seeks to impose authoritarianism everywhere in culture and the media,” the authors wrote.

In the film industry, where Bolloré has long dominated private production, cinema insiders said they had been emboldened to speak out after the publishing revolt.

Bolloré controls the entertainment conglomerate Canal+ and its in-house production operation, StudioCanal, which is Europe’s leading film and television production and distribution group. StudioCanal’s recent films include the Amy Winehouse biopic, Back to Black, and Paddington in Peru.

The film industry figures said they were alarmed that Canal+ had taken a stake in UGC, the third biggest network of French cinemas, with a view to fully owning it in 2028. They said Bolloré would be “in the position of controlling the entire fabrication chain of films from their financing to their distribution and their release on the big and small screen”.

They said that “behind his business suit”, Bolloré was promoting a reactionary, far-right project for society “through his TV stations, like CNews and his publishing houses” and they feared this could extend to film.

“The influence of [his] ideological offensive on the content of films has so far been discreet, but we are under no illusion: this won’t last,” they wrote. They called on the wider film industry “to build a movement” that would defend independence.

The open letter comes with Marine Le Pen’s far-right National Rally (RN) is polling high ahead of next spring’s presidential election and there is uncertainty about the scale of her party’s proposed funding cuts to the arts.

MPs for the RN have questioned the model of public funding and tax breaks that bolster the film industry through the Centre National du Cinéma (CNC), a state agency which supports the production of hundreds of films a year.

Le Pen’s party has also been highly critical of France’s public broadcaster, France Télévisions, which is a key financier of film, drama and documentaries. The RN has said it intended to privatise the state broadcaster if it came to power. A report last week by an MP allied to the RN called for sweeping cuts to public broadcasting, including to entertainment budgets.

The protest letter said Bolloré might take advantage of his dominant position to have an impact on film content.

“The unprecedented concentration of the financing chain in the hands of Vincent Bolloré gives him total liberty of action when the moment comes,” the letter said. “We cannot say we didn’t know. The dismantling of the CNC and the public broadcaster are part of the RN’s programme. Do we want to take the risk that tomorrow the only thing still being financed will be propaganda films that serve an ideology?”

Bolloré, a Breton industrialist, was once described by the former education minister Pap Ndiaye as “very close to the most radical far right”. In a senate hearing in 2022, Bolloré denied political or ideological interventionism, saying his interest in acquiring media was purely financial and his cultural empire was about promoting French soft power.

Bolloré’s group has not commented on the letter from film figures. After last month’s authors’ revolt over his publishing business, Bolloré wrote in Le Journal du Dimanche that those who had quit were “a tiny caste who think themselves above everyone else”. He said: “As for the attacks concerning my ‘ideology’, I’m a Christian democrat.”