55 yrs+ & own house for 10 yrs don't have to pay current property tax rate?

Someone told me that if you're 55 yrs or older and been living in your 1st home for over 10 yrs. If you buy the 2nd home, your property tax rate is based on the old home and not the new selling price. Is this true? if yes, where can i find the information? This is regarding California real estate law.