There are no additional expenses-taxes per se for foreigners when buying or selling real estate in California.
Profits from the sales will be taxed according to State and Federal Tax guidelines for foreigners, and some withholding will happen at sale.
I have worked with foreign investors before and I can put you in contact with tax attorneys that will assist you in determining your tax liability upon sale based on your citizenship and other factors.
Prudential California Realty
(323) 710-1770 direct