Situated on the Oder river, the border city of Frankfurt is linked to its Polish sister city Slubice by a bridge. At its best, the relationship between Frankfurt and Slubice makes the city seem like a poster-child for EU values. But a closer look at the graffiti on the city's walls points to an ideological battle bubbling under the surface.

With the rise of right-wing populism in Europe and the election of Donald Trump in the United States, the far-right is becoming an increasingly visible global political force. In Frankfurt (Oder), however, they are not alone. The city's graffiti reveals an accompanying far-left presence – the so-called Antifa.

Short for Antifaschistische Aktion, the Antifa movement can be traced back to 1930s Germany. However, according to the American left-wing magazine Jacobin, today's German Antifa has its roots in the 1990s. The movement allegedly reemerged in response to the growth of right-wing groups following the country's reunification.

Contemporary Antifa mostly comprises of autonomous groups that borrow from anarchist and socialist ideology and are united by a general belief in violence as a legitimate form of activism.

In Frankfurt (Oder), however, it appears that both the far-left and the far-right have opted for spray-paint and stickers as their weapons of choice.

On the city's central streets surrounding the European University Viadrina, lampposts and buildings sport a medley of right-wing and Antifa messages. This mingling makes much of the graffiti seem reactive – but it's often difficult to tell who's message came first. Antifa stickers are papered over nationalist ones and vice versa, key slogans and contact information are crossed out, and double negatives render the actual status of "anti-Antifa areas" ambiguous.

Across the river in Slubice, however, this graffiti battle is nowhere to be seen.

According to Rechtes Land, an online self-described "atlas of right structures and activities in Germany," both Frankfurt and Slubice saw a number of racist attacks in 2016. While their map indicates no Antifa presence on the Polish side, Frankfurt is home to an Antifa research group and the so-called Autonomous Antifa Frankfurt (Oder).

This apparent lack of a cross-border dimension could be explained by Frankfurt's Antifa graffiti artists' preoccupation with national politics. Ahead of Germany's federal election on September 24, these Antifa messages are often directed at the country's right-wing populist and Eurosceptic party – Alternative for Germany (AfD).

On the international level, Antifa protests in Germany recently gained media attention during rioting at the G20 Summit in Hamburg in July. In the United States, Antifa participation in counter-protests against far-right groups, including some violent actions, have sparked what is best described as a debate over the ethics of punching Nazis.

Meanwhile, in Frankfurt (Oder), graffiti forms an unlikely record of the far-left's encounters with the far-right.