PARIS, July 28 (Xinhua) -- France hopes leaders of G7 would agree on a universal tax of digital activities at the bloc' summit next month in France, French Minister of the Economy and Finance Bruno Le Maire said Saturday.

"We hope between now and the end of August -- the G7 heads of state meeting in Biarritz -- will reach an agreement," Le Maire told a press conference.

"The challenge that we have to overcome is the digital economy which is not taxed at the same level as the other economic activities," he said.

Austria, Britain, Spain and Italy have announced plans for their own digital taxes.

Le Maire justified the need to tax internet giants, saying that "it is in our collective interest to achieve a fair taxation of digital activities in the world."

Le Maire said that the digital tax on internet giants was "a national decision" that the government would enact, despite U.S. president Donald Trump's threats of retaliatory tariffs.

"If anybody taxes them, it should be their home Country, the USA," Trump tweeted on Friday. "We will announce a substantial reciprocal action on Macron's foolishness shortly. I've always said American wine is better than French wine."

The three-percent tax that went into force in France this week targets digital companies with yearly global sales worth at least 750 million euros (835 million U.S. dollars) and French revenue worth more than 25 million euros (27 million dollars).

The tax was adopted by France's National Assembly, the lower house of the parliament, on July 4. It is expected to collect 400 million euros (445 million dollars) this year and 650 million euros (723 million dollars) by 2022.

"They shouldn't have done this," Trump said in the Oval Office on Friday afternoon. "Don't do it, because if you do it, I'm going to tax your wine."

The U.S. Trade Representative (USTR) initiated an investigation on July 10 against France under Section 301 of the Trade Act of 1974, accusing the French government of "unfairly targeting the tax at certain U.S.-based technology companies."

The USTR will hold a public hearing on August 19 following the investigation, allowing the public to submit comments on any reciprocal action.