It is a property bubble ONLY IF their banks are handing out sub-prime mortgages. Only if they have similar laws and institutions as Fanny & Freddie. Only if their politicians are threatening the banks of serious investigations unless the banks grant mortgages to people who can never make the payments.
Note for many decades out properties kept on ascending merrily along, year after year with no problem. Only when the banks were blackmailed into giving out sub-prime loans the bubble burst.
I’m not sure about that — people buying second homes as investments are also a root cause of bubbles — at least in Spain
Certainly possible that its wealthy people from other nations buying there. A whole bunch of money has fled Spain,Greece and France to name a few.