François Hollande and Angela Merkel have condemned the behaviour of Turkish politicians ahead of the country’s upcoming constitutional referendum, saying it was “unacceptable” for Turkey to accuse Germany and other countries of “Nazi practices” for banning rallies in support of President Recep Tayyip Erdoğan.

In a phone call on Thursday, the French president expressed his country’s solidarity with Germany and other EU states that have been targeted with abuse ahead of a Turkish referendum on 16 April which could expand Erdoğan’s powers.

Germany and the Netherlands have been the principal targets of Turkish anger, after banning pro-Erdoğan rallies, but France has been inadvertently drawn into the row after confusion over Hollande’s surname. The French flag was burned during a protest in the city of Samsun and Erdoğan supporters targeted Hollande on social media.

In their joint statement, Hollande and Merkel said they agreed that Turkish politicians should be allowed to campaign in their countries, but only under the condition they stuck to German and French law and met “precise guidelines” such as early registration and transparency about campaign events.

German diplomats informed their Turkish counterparts earlier in the week that Turkish citizens living in Germany would be allowed to vote via 13 voting stations in cities across the country, but emphasised that Berlin could withdraw its offer if Turkey did not tone down its rhetoric.

But Turkey’s foreign minister, Mevlüt Çavuşoğlu, has continued his government’s harsh criticism of the Dutch. Çavuşoğlu told a campaign event in Antalya that there was no difference between the far-right populist Geert Wilders and other Dutch politicians. “The fascist Wilders and the social democrats are birds of a feather,” he said.

“They all have the same mentality. And this mentality will lead Europe to the brink. Soon there could be and will be religious wars starting in Europe.”

Europe needed to stop lecturing Turkey, Çavuşoğlu said, because “it is Turkey that commands”.

Diplomatic relations between Turkey and the EU have soured since the Dutch government stopped the Turkish family minister, Fatma Betül Sayan Kaya, from holding a campaign event in Rotterdam last weekend.