It isn't kosher. They import it from France. But the law, according to Wikipedia, doesn't prohibit importing foie gras if it was produced outside of CA.
I don't mean to bicker, but I stand corrected. Sale and production of foie gras is illegal in California however, consumption is. To quote Wikipedia "The state of California has also prohibited the production and sale of foie gras, effective 1 July 2012.[71][72] Violators will receive a $1,000 fine. Some restaurant owners have declared they plan to use a loophole in the new law; if restaurant goers bring in their own foie gras, restaurants may legally prepare and serve it.[73]"
I don't think any food establishment in CA is selling foie gras. Period.