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A Stolperstein literally "stumbling stone", metaphorically a "stumbling block" is a sett-size, 10 by 10 centimetres (3.9 in × 3.9 in) concrete cube bearing a brass plate inscribed with the name and life dates of victims of Nazi extermination or persecution.

The Stolpersteine project, initiated by the German artist Gunter Demnig in 1992, aims to commemorate individuals at exactly the last place of residency—or, sometimes, work—which was freely chosen by the person before he or she fell victim to Nazi terror, euthanasia, eugenics, was deported to a concentration or extermination camp, or escaped persecution by emigration or suicide. As of 29 March 2018, over 67,000 Stolpersteine have been laid in 22 countries, making the Stolpersteine project the world's largest decentralized memorial.

The majority of Stolpersteine commemorate Jewish victims of the Holocaust. Others have been placed for Sinti and Romani people (then also called "gypsies"), homosexuals, the physically or mentally disabled, Jehovah's Witnesses, black people, members of the Communist Party, the Social Democratic Party, and the anti-Nazi Resistance, the Christian opposition (both Protestants and Catholics), and Freemasons, along with International Brigade soldiers in the Spanish Civil War, military deserters, conscientious objectors, escape helpers, capitulators, "habitual criminals", looters, and others charged with treason, military disobedience, or undermining the Nazi military, as well as Allied soldiers.

Karl Klaar was a Jewish merchant, born on July 10, 1890 in Lengsfeld (Wartburg district). Trommsdorffstrasse 5 was his last place of residence. He also ran his business there, "Erfurter Tapisserie-Manufaktur Klaar und Schloss".  In 1936, the National Socialists expropriated the entrepreneur. As a result, Klaar lost his livelihood.

Since 1930, he had been placed in various sanatoriums, including in Pfafferode (Mühlhausen) and Hildesheim (Lower Saxony). Due to his Jewish origins and mental illness, Klaar was threatened in two ways by the Nazis. On November 28, 1940, he was reportedly murdered in the Bernburg killing center.

The brothers Erich and Wilhelm Dublon were co-owners of the shoe company Dublon. Their father founded the company in 1898 and was co-owner until his death in 1940. In the shop at Anger 46 they sold products from the Hess shoe factory. Opposite, at Anger 27, they ran the Salamander shoe shop. In May 1938 they had to give up this business after Salamander and Hess withdrew their representation.

A year later, Wilhelm, his wife Erna (born 1903), their daughters Lore (born 1927) and Eva (born 1933) and Erich Dublon boarded the refugee ship "St. Louis" in Hamburg. Erich kept a diary on the way. The failure of their escape went down in history as the "Error Voyage of the St. Louis".

The Dublons found refuge in Belgium and came under the control of German fascism in 1940. Wilhelm was interned in Mechelen on December 23, 1943, his wife and their two children on January 8, 1944. Seven days later, the deportation of the family to the Auschwitz extermination camp began. Erich had already been transported from Mechelen to Auschwitz in August 1942. The death register of the Auschwitz extermination camp records his death on September 3, 1942.

Doctor Dr. Ernst Ehrlich was born on July 13, 1874 in Beuthen, in what is now Poland. He studied medicine in Berlin and Breslau and was established in Erfurt as a specialist in gastrointestinal and metabolic diseases on April 19, 1902. Between 1933 and 1938 he lived and practiced on the first floor of the building at Bahnhofstrasse 40.

As a former Jewish front-line soldier and a doctor who had been established before August 1, 1914, Dr. Ehrlich was still exempt from the ban on practicing as a statutory health insurance doctor in 1933. From October 1938, the professional ban affected all Jewish doctors. On November 9, 1938, he was arrested and the next day, along with 179 other men, transported from the gymnasium of the Realgymnasium to the Buchenwald concentration camp, where he remained imprisoned until November 26, 1938. From July 1939 he was the last "medical practitioner" in Erfurt, i.e. he was only authorized to treat Jews. Dr. Ernst Ehrlich died on October 13, 1942, at the age of 68, in Theresienstadt ghetto as a result of the inhumane living conditions.

The four-year-old was the youngest Erfurt resident to be deported. He lived with his mother and grandparents on the second floor of what was then Friedrich-Wilhelm-Platz 23 with the Satonower sisters. Günther's father had emigrated to Holland with the intention of bringing his wife and child with him. Günther came to Erfurt from Glogau with his mother Irma in September 1939. The mother's parents had moved from Stadtlengsfeld in 1938.

In 1941, Irma Beer did forced labor at Amend & Co. On May 8, 1942, the Satonowers and their subtenants had to deregister with an unknown destination. On May 9, 1942, they reached the assembly camp in Weimar and the following day they were deported to the Lublin district. The first mass deportation of Jews from the Thuringia and Saxony area affected 101 people from Erfurt. Not one of them survived.

In the summer of 1942, the Cohn family was moved into an apartment on the first floor of the rear building. Max Cohn was married to a non-Jew, and their three children were considered "first-degree Jewish half-breeds." The father of the family was employed as a forced laborer at the Thüba company, a Thuringian bath stove factory, in the manufacture of aircraft parts. A colleague denounced him in 1942 for exchanging cigarettes for food rations. Max Cohn was then arrested and convicted. After serving his sentence, he was imprisoned in the Auschwitz-Monowitz concentration camp. In November 1943, he was transferred to the Buchenwald concentration camp. He probably died there on April 9, 1945.

His eldest son Helmut and his daughter Rosemarie were denounced several times by neighbors for not wearing the Star of David. In mid-1944, both were arrested by the Gestapo and deported to the Auschwitz concentration and extermination camp in July 1944. The last sign of life from Helmut is a letter dated December 9, 1944 from the "infection block." On January 25, 1945, he arrived at the Mauthausen concentration camp on an "evacuation transport." A few days later, he was transferred to the Ebensee subcamp, where he died on March 27, 1945. Rosemarie was transferred to the Bergen-Belsen concentration camp, where she died of starvation in January 1945.

The property at Johannesstrasse 98/99 at the time is considered a ghetto house because several apartments were used by the Gestapo and city administration as "Jewish living space." At least another 17 people were deported from this residence between May 1942 and January 1945; only three of them survived.