According to the archdiocese, he said on Wednesday night: "What the Patriarch of Moscow says is heresy."
Orthodox Patriarch Cyril I had repeatedly stood behind the policies of Russian President Vladimir Putin and called the Ukraine war a "Holy War."
During a panel discussion at the third theological peace symposium on the occasion of the Munich Security Conference, Marx continued: "We see everywhere an instrumentalization of religion, some religious leaders love proximity to power."
He stressed: "Religion must not stand by the side of the powerful, but must stand by the side of the weak and victims."
In addition, religious representatives should not place themselves above others in their claims, because every person is a picture of God and "we are all brothers and sisters," according to Marx.
Europe must remember values
Marx noted parallels between Russian propaganda and statements in U.S. politics.
In both, there are more anti-liberal, freedom or solidarity-undermining tendencies.
He demanded that Europe, on the other hand, must reconsider its values: "We need a renewal of our position, our ideas, an understanding of our common values."
Several states have imposed sanctions on Cyril I because the head of the church, as a key ally of Putin, supports the war against Ukraine.