President Donald Trump Joshua Roberts | Reuters

President Donald Trump could fight back against France's new tax on U.S. technology companies by unleashing biting tariffs on key French goods, according to trade experts. The French Senate on Thursday passed a 3% tax that will affect American firms such as Facebook and Google. The tax, already approved by France's National Assembly, would apply to companies that draw about $850 million in revenue worldwide from digital services — and about $28 million from within France. Ahead of the tax's passage, the Office of the U.S. Trade Representative started an investigation into whether the measure "is discriminatory or unreasonable and burdens or restricts United States commerce," U.S. Trade Representative Robert Lighthizer said Wednesday. Once it finishes the probe, the agency could retaliate with tariffs or other steps to deter France — and potentially other countries — from putting new taxes on top U.S. companies. "Once the investigation is complete, USTR will determine based on the findings of the investigation whether and what action should be taken," the USTR said in a statement Thursday when asked how the administration could hit back at France. The probe under Section 301 of the Trade Act of 1974 could take up to a year, according to Jennifer Hillman, a Georgetown Law professor and former USTR and World Trade Organization official. She expects it to end "much faster" than that, and thinks "chances are high" that the Trump administration will find a violation.

French wine drinkers beware

The Trump administration will most likely respond by slapping tariffs on iconic French goods, experts said. That could mean duties of up to 100% on signature French products. Think wine, cheese or perfume. "I would expect steep tariffs on a very symbolic product, which is obviously the French spirits and wine industry. ... That's symbolic, and it does hurt economically, as well," said Jorn Fleck, associate director of the Future Europe Initiative at the Atlantic Council. In a CNBC interview last month, Trump suggested he could put tariffs on French wine. He said California wine producers have complained to him about France putting higher tariffs on imports than the U.S. does. "And you know what, it's not fair. We'll do something about it," he said. France exported 3.2 billion euro (about $3.6 billion) in wine to the U.S. last year, making America its biggest export market, according to the Federation of French Wines and Spirits Exporters.

Trump's other options to retaliate against France