European far-right leaders have praised Rishi Sunak’s illegal immigration bill, after a senior EU official repeated her doubts about the legality of the plans. “Bravo,” wrote the Alternative für Deutschland party on social media. “Way to go! The current [British] government plans now to deny asylum to illegal immigrants and fly them out to Rwanda,” the party wrote on Facebook, saying Germany should follow this approach. “When will we finally have it?” Éric Zemmour, the French far-right commentator, who came fourth in the race to succeed President Emmanuel Macron last year, also praised Sunak’s new policy. “The message is clear,” he wrote on Twitter. “Congratulations to the British prime minister who, unlike Macron’s government, has chosen to protect his people against submersion by migrants,” said Zemmour, a proponent of the “great replacement theory” that Muslim immigrants are replacing native Europeans. Italian far-right leader Matteo Salvini retweeted a tweet by Sunak that had been translated into Italian and set out the government’s messaging on the bill, including the line, “if you arrive illegally in the UK, you can’t claim asylum”. Salvini, who is Italy’s deputy prime minister and heads the far-right League party, described the policy as “harsh, but fair”. The EU migration commissioner Ylva Johansson, however, said she had told Suella Braverman that her plan violates international law, after the home secretary called her to explain the bill. “Of course, I hope that it will respect the international agreements and the Geneva convention, but I must say that my first impression was that I’m afraid that there might be violations here,” Johansson told reporters on Thursday, promising further study of the draft legislation. “You have to have some kind of individual assessment of people coming before you just put them into detention,” the Swedish commissioner had previously told Politico. Under the government’s plans, adults arriving in the UK on small boats or in the back of a lorry would be denied the right to claim asylum, even if they had come from a war zone or faced persecution in countries well known for human rights abuses. Instead people would be sent back to “a country or territory to which there is reason to believe [they would] be admitted”, the country that they had embarked from to the UK, their country of origin or another country where they held a passport, according to the draft bill. Big questions remain over which countries would take in tens of thousands of people denied asylum in the UK – last year 45,755 men, women and children crossed the Channel in small boats. While the government has suggested the majority would be sent to Rwanda after an agreement with Kigali, that arrangement is being challenged in the courts. Even if it does succeed, it is expected that only about 200 people would be transferred. The UK lost the right to return migrants to the EU after Brexit, although in practice relatively few people left the UK on such routes. Under the EU system, British authorities were also obliged to consider taking in asylum seekers with family ties in the UK. Speaking on Thursday, France’s interior minister Gérald Darmanin said the government’s illegal immigration bill “obviously must not have negative consequences on the bilateral relationship” between France and Britain. His comments came on the eve of a long-awaited Franco-British summit on Friday that Paris hopes will turn the page on disastrously bad relations under Boris Johnson and Liz Truss. Attending a meeting with his EU counterparts in Brussels, Darmanin said any agreement on asylum seekers with the UK would have to be via the EU, rather than a bilateral deal with France. “It is not a bilateral treaty, it is not a treaty between France and Great Britain, since France in this precise case is the route for [migrants coming through] the whole European Union to go to England. And so we all have to work collectively, the European Commission, Great Britain and of course [EU] member states for an agreement between the European Union and Great Britain on the question of legal routes to Great Britain and then on the question of returns as well.” Sweden’s interior minister, Maria Malmer Stenergard, suggested a returns agreement with the UK was not on the EU’s agenda. She said she could not comment on the specifics of the British proposal, adding: “Generally, I expect that countries will have legislation that is in accordance with international law and the right to seek asylum … the question regarding readmission agreements will also have to be dealt with later.”