One of Poland's leading journalists and intellectuals has been awarded the Goethe medal in recognition of his "outstanding" contribution to the dialogue between eastern and western Europe.

Adam Michnik, a onetime Solidarity activist and now publisher of Gazeta Wyborcza, Poland's biggest newspaper, was given the award for his commitment to the German language and international cultural relations.

The two other winners this year were the British novelist David Cornwell, better known as John le Carré, and the French film and theatre director Ariane Mnouchkine.

Michnik, a former dissident who spent six years in prison for agitating against the communist regime, has since become one of the most influential figures in modern democratic Poland.

He was once described by Václav Havel, the first president of the Czech Republic, as "the intellectual conscience of the Polish nation".

Speaking at the Amnesty strand of the Edinburgh book festival last week – sponsored by the Guardian – Michnik recalled his time in jail as one of Amnesty's causes and said he still couldn't believe he was a free man.

"I often wake up in the morning and I'm afraid to open my eyes because I worry that it will turn out the last 20 years were just a dream.

"It will turn out that Brezhnev is still alive and that they are going to come and knock on my door and I will be wondering if they are going to arrest me in the Polish language or the Russian," he said.

At the awards ceremony in Weimar on Sunday, Klaus-Dieter Lehmann, president of the Goethe Institut, said Michnik had "played a key role in ensuring that Poles and Germans now once again have a positive common story to tell".

Michnik, Lehman said, was "a brave, incorruptible and tolerant Polish rebel who has never tired of speaking out in the European public sphere".

After the prizegiving, Le Carré gave an address devoted to his "love affair" with Germany which also touched on the problems facing his native Britain – which was, he said, suffering from "a moral vacuum" in the wake of the riots and phone-hacking scandal.