Major tech firms and US tech industry groups said that France’s new digital services tax undermines the global tax regime and multilateral efforts to reform it.

Google, Facebook, Amazon.and major trade associations testified Monday against the tax at a hearing before the US Trade Representative’s office and other government officials.

The French Senate in July approved a three percent levy that will apply to revenue from digital services earned in France by companies with more than 25 million euro in French revenue and 750 million euro ($838 million) worldwide.

The US Chamber of Commerce said the tax will generate revenue of approximately 500 million euro ($554 million) per year “a large majority of which will be paid by US firms” and will cost US firms millions to conduct “significant re-engineering of accounting systems to ensure that they can accurately assess” liability.

Major tech firms warned of increased costs.

“Unilateral measures like the DST are harmful to Facebook and the digital economy,” Alan Lee, Facebook’s global head of tax policy, said in a statement.

Matthew Schruers, chief operating officer at the Computer and Communications Industry Association (CCIA), representing companies like Intel, eBay and Netflix said at the hearing that the tax “undermines the progress made” on a new tax system on the digital economy and “supports an aggressive response to this problem.”

“CCIA believes that this action warrants a substantial, proportionate response from the United States,” Schruers said, adding the tax “unquestionably” targets US firms in an attempt by the French government to “ringfence” them.

Amazon’s international tax policy director Peter Hiltz said more than 10,000 French-based businesses are selling on Amazon’s online stores and notified them certain fees will increase by three per cent  for Amazon.fr sales starting 1 October.

Last month, President Donald Trump threatened to tax French wines or other products in response. USTR could impose new tariffs after a public comment period ends 26 August.

Other EU countries have also announced plans for their own digital taxes, arguing a levy is needed because big, multinational internet companies book profits in low-tax countries like Ireland, no matter where the revenue originates.