Good. Next step, have EU countries come up with an estimation of the value of their citizens' private data that FB and Google gobbles up and tax them on that too.
Edit: companies -> countries
Edit: companies -> countries
Also, no. Social media existed before the current big general-purpose networks. See Usenet, email lists, IRC, forums, etc. A single big network with no particular purpose or common interest provides different benefits, better in some ways and worse in others, but niche networks still have their own worth.
You said: Or do you expect these companies would continue to operate in the EU with no net profit.
A tax doesn't have to eat up all the net profit. Googling "how much is a Facebook user worth" comes back with about $158 dollars, whether that's accurate or not is beside the point, some value can be derived[1], France can say "we want a X% tax on that value". If the tax is too high FB leaves the market and France gets nothing so there is little incentive to do that[2]. FB then has to take the cost of servicing a user against their value minus the tax and decide if they want to continue as is, offer a paywall option to avoid the tax, or leave the market altogether... I don't understand why this would be so controversial?
[1] Whether FB or regulators should set that value is up for discussion.
[2] Some would see FB as such an overwhelming societal net negative they would want to tax it out of existence, but that could be true for any industry (fossil fuels, tobacco , meat, etc...)
Making people pay to access Facebook etc would be the best possible move for society ever.
Regulators are not quick, give them a year or two to deliver the fines.
E.g. facebook could be forced to give you discounts for your card or sth.