California requires you to add back the contribution, however the state doesn't have an excess contribution penalty like the federal. Effectively, the law just turns the contribution into a nondeductible contribution.
You will need to keep track of this nondeductible contribution. When you withdraw from your IRA, the full amount will be taxable on the federal return but not for California. You will need to make an adjustment on your California return to reduce your income by the amount that considered nontaxable for that year.
