Turkey's foreign minister, speaking in France, said that the Netherlands is the "capital of fascism". He made the remarks on Sunday, the day after he was barred from speaking in the country to promote a referendum at home.

Earlier in the day, Turkish President Tayyip Erdogan said the Netherlands would pay the price for harming relations between the two countries, as a row over Ankara's political campaigning among Turkish immigrants escalated on Sunday.

Some 800 flag-waving Turks gathered in the eastern French city of Metz for the address by Mevlut Cavusoglu, who is campaigning for constitutional changes that would boost the powers of Turkish President Recep Tayyip Erdogan.

The "fascism" comment echoed accusations by Erdogan himself, both Saturday and again on Sunday, when he said the Netherlands was behaving like the Nazis in its treatment of Turkish ministers.

The Metz rally, which had the blessing of the French authorities, was planned weeks ago but took on "another dimension" because of the row between Ankara and The Hague, said Saban Kiper, vice president of a grouping in France of Turkish associations.

"France has a more serene attitude than the Netherlands," he said.

French Foreign Minister Jean-Marc Ayrault said in a statement there was "no reason to prohibit this gathering that poses no possibility of interference in French political life."

(With inputs from AFP & Reuters)