US President Donald Trump has ordered an investigation into France’s planned tax on internet and technology giants.
“The United States is very concerned that the digital services tax… unfairly targets American companies,” the US trade representative said on Wednesday.
The French parliament is expected to approve the new tax on Thursday.
It will target companies such as Google and Facebook with a 3% levy on revenue made inside France.
It is expected to raise about 400 million euros ($450m; £360m) this year.
Any digital company with a revenue of more than 750 million euros – of which at least 25m is made in France – would be subject to the tax.
“[Mr Trump] has directed that we investigate the effects of this legislation and determine whether it is discriminatory or unreasonable and burdens or restricts United States commerce,” the statement from trade representative Robert Lighthizer said.
The US investigation could pave the way for punitive tariffs, which Mr Trump has imposed on several occasions since taking office.
Previous investigations launched by Washington have covered European Union and Chinese trade practices.
The French government has argued that companies should not be able to escape paying tax if their headquarters are based elsewhere.
Its initiative is a response to a growing public feeling that countries are losing out on billions in taxes because of the intangible and extra-territorial nature of the digital economy, BBC Paris Correspondent Hugh Schofield says.
Around 30 – mostly American companies – will pay the tax. Chinese, German, Spanish and British firms will also be affected.
The UK has said it is studying a similar digital services tax.