Four years after Greece’s former “rock-star finance minister” clashed with his northern European counterparts over austerity measures and debt relief, Yanis Varoufakis is once again taking the fight to his old enemy.

This time, he hopes to make friends rather than foes: at the end of this month, Varoufakis will try to convince voters to elect him as a member of the European parliament – not in his native Greece, but in Germany.

But along the way he is also managing to alienate old allies, who say his campaign isn’t so much “democratising Europe” as splintering the leftwing vote at times of a far-right revival.

Along with the Austrian-German economist, Daniela Platsch, and Croatian philosopher, Srećko Horvat, Varoufakis is one of three pan-European candidates competing for a vote on 26 May with “Demokratie in Europa,” a small German political party which, in turn, is an offshoot of the Democracy in Europe Movement 2025, or DiEM25 for short.

A German candidate is representing DiEM25’s offshoot MeRA25 in Greece – a deliberate move, Varoufakis said in a Guardian documentary that follows his campaign, to “signify the current struggle is not between the Greeks and Germans”, but “between progressive rational humanist policies on the one hand, and authoritarianism on the other hand”.

Varoufakis and Horvat were able to get their names on the ballot in Germany simply by registering in time as residents of Berlin with the local authorities. German law states that a candidate must be a citizen of an EU country and have resided in Germany for at least six months.

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“We are being more German than the Germans,” said Horvat, candidate number three behind Varoufakis and Platsch. “We are just following the rules.”

DiEM25 calls for a “new green deal for Europe” in the shape of €500bn annual investment in environmentally friendly infrastructure and renewable energy, and propose live-streaming European summits and meetings of the European Central Bank.

In order draw attention to their policies, the party has largely shunned conventional campaign methods, such as street rallies, and relied instead on celebrity support. This week, later than its competitors, DiEM25 put 1,000 posters across Berlin bearing the image of the former Baywatch actor Pamela Anderson, who is not a member of the party but describes herself as a supporter.

Facebook Twitter Pinterest A DiEM25 poster in Germany featuring Pamela Anderson. Photograph: DiEM25

In a statement, Anderson said she supported DiEM25 because “they are the only ones putting forward a comprehensive and inspiring green new deal for Europe. […] I know this poster is a little crazy. But it’s time to get out there and do whatever it takes to get people’s attention.”

Horvat said they had decided to use the Playboy-model-turned-activist in its campaign “because German political posters are utterly boring”, but also “because it shouldn’t be just Steve Bannon exploring new modes of political action and agitation, we have to use our imagination and subvert the dominant paradigm of political communication”.

But the party’s approach to campaigning has also alienated many politicians from the one political party that showed solidarity with Varoufakis’s cause at the height of the Greek debt crisis.

“In principle I am a fan of the idea of a Greek politician running as an MEP in Germany,” said the veteran Die Linke MEP, Gabi Zimmer, “not least because the German government has been one of the biggest supporters of harsh austerity measures in southern Europe. But I am starting to question whether Mr Varoufakis is truly committed to the cause he claims to advance.”

Delegates from Die Linke visited Athens at the height of the Greek debt crisis to show solidarity with Varoufakis’s former party Syriza, and its co-chair Katja Kipping attended the launch of DiEM25 in Berlin in 2016. But the ex-finance minister’s announcement that he would give up his MEP seat “within weeks” of being elected has confused many of his former allies.

“DiEM25 say they want to democratise Europe, but Varoufakis says he would step down from his post to campaign for the Greek elections in the autumn,” said Zimmer, who has been an MEP since 2004. “That’s nonsense, and has very little to do with democracy. If you want to strengthen democracy, you have to strengthen the European parliament. It’s very disappointing.”

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Jörg Schindler, the federal executive director and chief whip of Die Linke, told the Guardian: “We are taken aback by the fact that DiEM25 prefers a splintered left to a strong European left that speaks with one voice. Then again, Mr Varoufakis has been quieter during the campaign than expected: so far, his party has not played a significant part in the run-up to the election.

“In times of a resurgent far-right we don’t need role-playing games with celebrities from 90s TV shows, but a strong leftwing alternative,” he added.

Unlike in Greece, there is no vote threshold for entry into the European parliament in Germany. At the 2014 elections, satirical group Die Partei were able to secure a seat in Brussels and Strasbourg with only 0.6% of the vote, and by DiEM25’s own calculation the party would need no more than 300,000 votes to send its first list candidate to the legislature.

The German constitutional court’s 2014 decision to scrap the vote hurdle, however, has also lead to a rise of minority interest parties, meaning DiEM25 will compete with an unprecedented 40 other parties on the ballot paper this year. According to Manfred Güllner, the director of leading German pollster Forsa, Varoufakis’s new outfit has not yet registered in any of its polls. “Support for DiEM25 is currently below any measurable level,” Güllner said.