During French President Emmanuel Macron’s visit to Washington last month, Trump reportedly told him that he would stick to his trade policy until “no new Mercedes models rolled down Fifth Avenue in New York.”

Last week, Trump had instructed his administration to look into any potentially damaging effects foreign imports might have over the U.S. auto industry, which could lead to an import tax as high as 25% on European cars, as reported by German news outlet, Wirtschaftswoche.

Such a tariff could lead German automakers (who control 90% of the U.S. premium car market), to conclude that exporting their models to the U.S. doesn’t make financial sense anymore.

Germany is also the biggest exporter of cars to the United States, with German automakers assembling 804,000 vehicles in the U.S. last year, while exporting another 657,000, reports Autonews.

Of course, Trump’s grudge against German premium brands goes back to January of last year when he stated in an interview his displeasure for how many Mercedes-Benz models reside on Fifth Avenue in NY.

“When you walk down Fifth Avenue, everyone has a Mercedes-Benz in front of their house. How many Chevrolets do you see in Germany? Not too many, maybe none at all, you do not see anything over there, it’s a one-way street.”

If Trump does stick by his aggressive policy, Germany has warned that the end result could be a damaging trade war.