Michel Barnier promised to crack down on immigration and compared France’s borders to “sieves” as he signalled a shift to the Right in his first interview as the country’s prime minister.

The remarks came as Left-wing parties accused the hard-Right National Rally (RN) of exercising outsize influence over the new prime minister and called for nationwide demonstrations.

Speaking to national broadcaster TF1 on Friday, the former Brexit negotiator said: “There still is a feeling that our borders are sieves and that migration flows aren’t being controlled.

“I don’t have much in common with the ideologies of the National Rally, but I respect it.”

Emmanuel Macron nominated Mr Barnier as prime minister on Thursday, ending a two-month search for a candidate that would not be vetoed by a hung parliament that includes large voting blocs representing the RN and the New Popular Front, a Left-wing alliance.

Mr Barnier, 73, is a conservative and the nomination relied on tacit support from the RN, which said it would not veto his nomination.

The move infuriated Left-wing parties, who together won the most votes but who Mr Macron overlooked when they failed to win an outright majority in July’s National Assembly election.

Lucie Castets, the NPF’s candidate for prime minister, said Mr Barnier “is completely dependent on the RN”.

Jean-Luc Mélenchon of France Unbowed, a hard-Left party, called for marches across France on Saturday.

In an apparent attempt to address allegations of Right-wing bias, Mr Barnier said he would draw on talent from across the political spectrum in forming his government.

“There is no red line”, he said of his likely choices for ministers. “We need to open the door ... to all those who want it.”

Mr Barnier said talks between centre-Right conservatives and centrist supporters of Mr Macron on forming a cabinet were going well.

But he also said Left-wing party members would be welcome.

Mr Barnier added that he would press ahead with some of Mr Macron’s flagship policies, including an unpopular reform that would raise the retirement age from 62 to 64.

RN and NPF, who together control a majority in the new parliament, both bitterly opposed the reform.