CA Prob Code Section 17000

(a)

The superior court having jurisdiction over the trust pursuant to this part has exclusive jurisdiction of proceedings concerning the internal affairs of trusts.

(b)

The superior court having jurisdiction over the trust pursuant to this part has concurrent jurisdiction of the following:

(1)

Actions and proceedings to determine the existence of trusts.

(2)

Actions and proceedings by or against creditors or debtors of trusts.

(3)

Other actions and proceedings involving trustees and third persons.