The Turkish Foreign Ministry has summoned Germany's charge d'affaires in Ankara to protest a decision that prevented President Recep Tayyip Erdogan from addressing a rally in Cologne via a video link.
Thousands rallied in the German city on July 31 to denounce the failed July 15 coup in Turkey and show support for Erdogan.
Local police had initially banned the organizers from erecting a large video screen at the demonstration.
A regional court later ruled that a large screen could be used, but only to relay the speeches of people physically present at the rally.
The decision was confirmed by Germany's highest court.
Turkish Deputy Prime Minister Numan Kurtulmus on August 1 said the move was contrary to freedom of speech and accused Germany of "double standards."
There are about 3 million ethnic Turks living in Germany, Turkey's largest diaspora community.