Foreign social security is taxable by California as annuity income. A tax treaty between the United States and another country which excludes the foreign social security from federal income or which treats theforeign social security as if it were United States social securitydoes not apply for California purposes.
https://www.ftb.ca.gov/forms/2011/11_1005.pdfFor federal tax purposes, social security payments received from France are taxable only in France.
"pensions and other payments made under the social security legislation of a
Contracting State to a resident of the other Contracting State shall be taxable only in the
first-mentioned State."
Based on this, a social security payment made by France to a resident of the US will be taxable in France Only.
