Organizers from the Free Deniz campaign kicked off the recital in Frankfurt's Schauspielhaus on Sunday with a plea for the German government to do more to secure Yucel's freedom.

"We now have to start thinking about economic sanctions," Doris Akrap of the German daily Die Tageszeitung told the 800-strong audience. "That's the only kind of pressure (Turkish President Recep Tayyip) Erdogan understands."

Prominent writers, actors and other German personalities took to the stage during the two-hour matinee to read excerpts from Yucel's reporting on topics as diverse as right-wing populism, German football, and political developments in Turkey. 

Yucel, a correspondent for Berlin daily newspaper Die Welt, has been in prison in Istanbul since the end of February. The 43-year-old is accused, among other things, of incitement to hatred and producing terrorist propaganda for the outlawed Kurdistan Workers' Party - allegations he denies.

Other speakers included veteran journalist Carolin Emcke, Yucel's sister Ilkay, and satirist Jan Böhmermann, who read several letters Yucel had written from his prison cell. The TV host ended the recital with a rendition of the 18th century German folk song "Die Gedanken sind frei" (Thoughts are free).

Böhmermann himself got into trouble with the Turkish government last year after he recited a lewd poem about Erdogan live on German television. The incident sparked a diplomatic crisis between Germany and Turkey.

"Turkey is on its way to becoming a totalitarian rogue state," said another speaker, German Publishers and Booksellers Association Director Alexander Skipis, adding that more than 130 journalists and authors are imprisoned in Turkey. Many were rounded up in the wake of last year's failed coup.

The Free Deniz campaign plans to hold similar recitals in solidarity with Yucel in Munich and Cologne.