“The book industry has always reacted with great sensitivity to the political climate,” she said, “and bookstores are always a place where social change occurs.” In the 1970s at the height of the women’s liberation movement, for example, Germany had large numbers of feminist bookstores. “Now, the theme really seems to be freedom of speech, freedom of opinion. Look at America, look at Turkey — this problem is all over the world.”

In German bookstore circles, the topic of nationalism and fascism is particularly prominent now, Ms. Hahn added. This follows the rise of groups like the Patriotic Europeans Against the Islamization of the West and Alternative for Germany, or AfD, which won 12.6 percent of the national vote in September, making it the first far-right party to sit in Parliament in 60 years.

“In every book there’s a new perspective,” Ms. Hahn said, “so bookstores automatically fall on the side of openness and diversity.”

But how best to serve customers is up for debate. In one of several panels dealing with the topic at the Leipzig Book Fair in mid-March, some independent sellers said they refused to order books from far-right publishers, while others argued that it is important for customers to be able to stay informed. (There are certain titles that Mr. Braunsdorf does not stock. He may order from some right-wing publishers upon request, but will give the customer a piece of his mind on the topic, first.)

Germany has a healthy number of independent bookstores, thanks largely to a German law that requires all booksellers to sell books at set prices. But Zoë Beck, co-founder of a group called Publishers Against the Right, worries that market-oriented chain stores have weakened bookstores’ role as a place of political debate. “What Jörg Braunsdorf is doing is something I find exemplary,” wrote Ms. Beck, in an email. “The need now is greater than ever.“

For Mr. Braunsdorf, 58, social engagement has always been part of running a bookstore. Originally from Wetzlar, a small city in what was then West Germany, Mr. Braunsdorf started working in his 20s at a book collective there run by a group of his young left-wing friends. They did not do much business, but the shop was a meeting place for students and activists: There, they printed fliers decrying nuclear power plants or calling for affordable housing.