An employee of the museum at a former Nazi concentration camp has been charged with anti-Semitism, along with five other men.
The six men were arrested and charged with incitement to commit hatred after three of them were found putting up posters which read "Zionists Leave Lublin" in the eastern Polish city.
It is alleged one of the men worked as a graphic designer at the museum at the former Majdanek death camp, and even used office equipment to print off the anti-Semitic posters.
The other three men were arrested at their homes, police said.
"We're shocked by these revelations," museum spokeswoman Agnieszka Kowalczyk-Nowak said told Polish news channel TVN.
"We've launched an internal investigation at the museum. Management has decided to suspend him from duty while the case is being clarified."
Police added the group, which also includes a local businessman, have been hanging the posters around Lublin since 2010. The men face up to seven and a half years in prison if found guilty.
An estimated 80,000 people were murdered by the Nazis in the infamous Majdanek, three-quarters of them Polish Jews, from 1941 to 1944.
The Lublin revelations came to light on the eve of Holocaust Memorial Day, an annual day of remembrance for those Jews who lost their lives.