The G-20 meeting in Mexico last 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 in order 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.