SERRAVAL, France — The two most respected newsweeklies in Germany, Der Spiegel and Die Zeit, are both based in Hamburg, and both were founded by icons of postwar journalism in Germany. But now their businesses seem to be headed in opposite directions.

This month, as Der Spiegel, a magazine, was firing its top two editors amid a long slump in circulation, Die Zeit, a newspaper, was celebrating record sales and big gains in advertising.

Their diverging fortunes underscore different approaches to news publishing in the digital era.

Der Spiegel has been the standard-bearer for investigative reporting in Germany since 1962, when its founder, Rudolf Augstein, prevailed in an important test of free speech for the still young Federal Republic of Germany. In the so-called Spiegel Affair, Mr. Augstein was arrested and accused of treason after the magazine published an exposé on the sorry state of German military readiness. The heavy-handed approach, orchestrated by the late Franz-Josef Strauss, then the defense minister, backfired, and Mr. Strauss was forced to resign.

Der Spiegel still prides itself on its adversarial tone. Last year, an advertising campaign for the magazine showed a picture of an editorial meeting, with the tag line, “the conference that makes politicians tremble.”