François Hollande is to press Barack Obama on tax avoidance by big Silicon Valley companies such as Google, saying that the practice of shifting tax liabilities around Europe was "not acceptable".
Hollande will meet Obama on Monday as part of a two-day trip during which he will also meet firms including Google, Facebook and Twitter in Silicon Valley.
The French president, who has sought higher taxes for big earners, said France would not continue to tolerate large companies' tax optimisation strategies.
"This is not acceptable and that is why, at both the European and the global level, we must ensure that tax optimisation ... can be called into question," Hollande said. His comments follow reports that France is seeking €1bn (£830m) in tax from Google over its fiscal strategies.