Facebook, Amazon and Apple have come under similar French scrutiny, according to published reports and public filings. Marini said French law is lagging behind, but hopes to catch up. Tech companies differ from, say, a grocery store in that their product is stored on servers and not on a shelf. And unlike a family, the companies can essentially locate -- and re-locate -- anywhere.
Both Amazon and Google are contesting the French actions, though Cahuzac said he's confident the government will win in court.
Britain and Germany have joined France in aggressively targeting the tech giants and, officials say, are coordinating against what one official calls "stateless income."
The G-20 meeting in Mexico earlier this month showed a measure of international support for tightening the rules. The U.K. Treasury chief George Osborne and German finance minister Wolfgang Schaeuble called for a common front "to strengthen international standards for corporate tax regimes."
"Governments have to keep up in the race," said Marini, the French senator. "Companies have a much faster pace than either national or European law."
Helping the governments keep tabs on the tech multinationals is the Organization for Economic Cooperation and Development. Originally set up in 1948 with the aim of stimulating world trade, the OECD now is taking the lead role in fighting tax evasion, said Pascal Saint-Amans, director of the organization's Center for Tax Policy since February.
The OECD has established a locked database detailing some of the world's most sophisticated tax schemes to allow government tax authorities to privately share revenue-shifting schemes they encounter.
The main problem, for Saint-Amans, is that tax havens within Europe such as Ireland and Luxembourg ease the process that allows multinationals to send profits even further offshore to places like Bermuda. That makes it harder for the countries with the most staff and sales to track. Google, Apple, Microsoft and Facebook have international headquarters in Ireland; Amazon's international offices are in Luxembourg. But the biggest European markets for all those companies are Germany, France and Great Britain.
"At some point again you're back to the basics, which is where is the real activity? And that's something that we may have lost sight of," said Saint-Amans. "The low-tax regimes are more the consequence than the problem."
Saint-Amans, who previously worked on ending bank secrecy regulations, believes the problem of taxing "intangibles" can be similarly resolved in a year or two with a concerted effort from all the governments involved, including in the U.S. In the short-term, he said, the coordinated approach of France, Germany and Britain serves as a warning to multinationals trying to avoid taxes, as is the secure OECD database.
Governments, including in the U.S., have long tinkered with effective tax rates to attract and keep businesses. But there are signs of change even in the U.S., where all the major tech companies got their start.
"The ability not to pay tax on income that's booked offshore is now the single biggest corporate tax loophole in the code," said Reuven Avi-Yonah, an international tax expert at the University of Michigan who has testified before Congress.
The amounts booked offshore are considerable: For Apple, 61 percent of revenues come from outside the U.S. -- and fully a quarter of that from Europe alone. "Apple doesn't have a single store in Ireland," Avi-Yonah said.
In a filing to the U.S. Securities and Exchange Commission, Apple said it had set aside $713 million for its 2012 foreign tax bill on overseas pretax earnings of $36.8 billion -- a provision of almost 2 percent of what it made.
Google's overseas revenues accounted for 54 percent of its total, including more than 10 percent in Britain alone. Meanwhile Google is tackling government action on another front. German politicians are considering imposing a so-called Google Tax -- a levy that would require search engines to pay each time they link to media content like newspaper articles or photographs.
According to a Senate committee memo from September, Microsoft used aggressive asset shifting to avoid $4.5 billion in American taxes from 2009 to 2011.Avi-Yonah estimated the effective tax rate on overseas income at about 2 or 3 percent for multinational tech companies: Both in the U.S. and abroad, he said, "there's a general sense that these companies pay too little and don't really contribute their fair share."