There is little in the world more portable that money. Google would have little problem conducting their French business from another EU country with a much lower tax rate such as Liechtenstein.
Google is not going to leave France. France has too large of a population and too large of an economy to just try and find loopholes around their tax code.
The taxes hadn't gone up. When it goes up, they'll move money as they already do.
Population is irrelevant. They are not a grocery store; no retail operations. They have no reason to stay in France if taxes go up. They can conduct business in France without being in France.
You think Google can't "outsource"? Of course they can and will. They aren't going to stand by and watch a French tax smash and grab. They will make them an example so that other EU nations don't try and follow suit.