France is reminding the US that threats are no way for allies to deal with each other, as the US "investigates" the plan to impose a tax on internet giants.

The "GAFA" tax imposes a three percent levy on total annual revenues of tech titans such as Google, Apple, Facebook, and Amazon.  Several other companies will be hit, as well as firms from Germany and other countries.  Officials hope it will raise 500 Million Euros a year.

But Donald Trump ordered an investigation of the tax, implying that the US could slap on French imports, which didn't sit well in Paris.

"France is a sovereign country, its decisions on tax matters are sovereign and will continue to be sovereign," said French finance minister Bruno Le Maire.  "Between allies, I believe we can and must resolve our differences in another way than through threats."

Le Maire lamented it was "the first time in the history of the relationship between the United States and France" that Washington decided to open such an investigation into French legislation.

France has tried to get other European Unions to pass identical tax laws, but they have resisted the idea.