"Heimwandern statt einwandern," which translates to "go home instead of immigrating," read the headline of a recent letter sent out by the German right-wing extremist party National Democratic Party of Germany (NPD). The letter was sent to candidates for German parliament who have a migration background as a means of intimidation.

"Your political influence on the German ethnic group might even be considered punishable from a human rights perspective," the letter read, which included a self-made, one-way ticket back to "the homeland."

Özcan Mutlu was one of the candidates who received the letter. He has Turkish roots and has represented the Green party in Berlin since 1999. His goal for this year is to gain a seat in the Bundestag, the lower house of German parliament. Mutlu was outraged by the NPD's letter. "I reported an offense against the disgusting NPD letter. Our home is Berlin and Nazis aren't welcome here!" he wrote on Twitter.

But the NPD isn't just after the Greens. Candidates from the Social Democrats Party (SPD) and the Pirate Party also reported receiving similar letters. Fabricio do Canto from the Pirate Party said the letter is a threat - not only to himself but also to his family. "Where did they get my address from?" he asked in the Berlin based newspaper "Prenzlauer Berg Nachrichten."

Xenophobia on election posters

It's not the first time that the NPD party has caused a stir with its election campaign. Previously, it gained attention with xenophobic election posters. Crude slogans such as "Minirock statt Minarette" (mini skirts instead of minarets) or "Heimreise statt Einreise" (head home not here) are among the party's regular political messages.

Protesters demonstrate against the right-wing extremist party in Berlin

"The party obviously thinks it can collect brownie points with the voters like this," said party researcher Uwe Jun of the University of Trier.

So far, such election posters have been more or less tolerated by society. But now several communities and cities are refusing to accept the NPD posters, which for instance read: "Geld für die Oma statt für Sinti und Roma" (Money for grandma instead of Sinti and Roma). The election posters were even placed above a road leading to the Mittelbau-Dora concentration camp memorial in the German state of Thuringia. The state's Interior Ministry has banned the posters.

Other German cities are also fighting against the NPD election posters. The city of Gießen has taken the posters down, because it considered them incitement. But the administrative court has ordered the city to put the posters back up. As a reaction, several parties sat together and started a counter campaign. "Meine Oma mag auch Sinti und Roma" (My grandma likes Sinti and Roma, too) is now written on their posters.

Fighting the extreme right with creativity and humor

Despite such campaign tactics, the NPD has denied being a xenophobic party. It refers to itself as "hostile to immigration " and writes on its website: "We don't have anything against Turks in Turkey." Party researcher Jun disagreed. "The party may deny the word 'xenophobic,' but what it cannot deny is that it doesn't like to see people from different cultural backgrounds in Germany."

So far all efforts to ban the National Democratic Party of Germany have failed.

The NPD has about 6,000 members and is active across all of Germany and is large enough to receive some federal funding for political activities. NPD representatives can currently be found in two German state parliaments, Saxony and Mecklenburg-Western Pomerania, and efforts to ban the party have failed. According to opponents of banning the party, the existence of political parties such as the NPD is less dangerous than having right-wing extremist groups operating underground.

Apart from protests and counter campaigns such as the one in the city of Gießen, NPD opponents also use humor to counter the right-wing extremist party. One example is a student who refers to himself as a "responsible and worried German with Turkish roots." He published a response to the NPD hate-letter on the Internet, which quickly went viral. His letter is composed in the same style as the one sent out by the NPD, which starts with the words "Hello migrant". The student - who wants to remain anonymous and - addresses the NPD with the words "Hello idiot."

The first paragraph of the NPD hate-letter reads: "The word 'migrant' derives from the Latin language. The Romans used to speak Latin until their powerful empire perished because too many immigrants invaded the realm and established parallel societies." The student's comeback: "The word 'idiot' derives from the Greek language. The Greeks speak Greek and their ancestors once invented democracy because too many idiots came to power and developed too many idiotic societies."

He later wrote: "Your political influence on the group of people that simply wants to peacefully live side-by-side might even be considered punishable from a constitutional perspective."

The student also called attention to the many spelling and grammatical mistakes in the NPD's letter. His ironic appeal to the party: "We should all make sure to preserve our beautiful German language."