On September 16, Germany introduced tighter controls at all the country’s land borders in what it called an attempt to tackle irregular migration and protect the public from threats such as Islamist extremism.

The new measures were a response by Chancellor Olaf Scholz’s government to regain the initiative on migration from the far-right, which has witnessed a surge in support following some violent incidents involving asylum seekers.

While checks had already been in place for some time along the borders with Poland, the Czech Republic, Austria and Switzerland, Germany imposed new controls along its northern border with Denmark and its western frontiers with Belgium, the Netherlands and Luxembourg.

However, according to FT, some Schengen supporters within the EU are concerned that Berlin’s decision could set a dangerous precedent, encouraging other countries to impose similar measures.

This could severely weaken the Schengen system of frictionless travel, which many in the EU regard as one of the greatest accomplishments of the European project.

“The mood has changed,” a senior EU diplomat told FT, adding: “There is no taboo on talking about this [border checks] anymore.”

Uwe Conrad, the mayor of Germany’s southwestern city of Saarbrücken, which borders France, warned of a “real danger of a domino effect.”

“Germany is a big country and what we do always has an effect on others,” he said.

Already, the new French Prime Minister Michel Barnier told parliament on Tuesday that France could expand its border controls “as permitted by European rules and as Germany has just done.”

Conrad added that Europeans must consider the question: “Do we want a Europe of open borders, or another kind of Europe entirely?”