In SF when you buy a house you are also competing with dozens of investors from overseas paying cash who don't have any intention of ever living there. I believe that the Vancouver real estate market was also affected by overseas investors in a similar way, making it the least affordable housing market in North America.
Multiply this speculative real estate investment by 1% of 7 billion and it could very well be a major factor in pushing up rents, especially in certain super desirable cities like Paris. There's about 1.7 million residences there. Even if only 1% of the 1% want a pied a terre there, the rest of the people trying to live there would feel the squeeze.
I have personally seen the effects of this. When I lived in on South 4th street in Williamsburg Brooklyn in 1998, my floor through apartment was $700/m. Now the same apartment is renting for $3700 a month. That particular street is still a dump! The only people I know who can afford to live in nice apartments in SoHo or Tribeca are the children of super rich people.