Legal Question in Criminal Law in California

The insurance citation is just an infraction, but an expensive one if convicted.

The falsification of registration charge, because it is a misdemeanor, it carries the possibility of time in county jail, probation, etc. If you truly had no knowledge the car was illegally registered, it may work in your favor. Unfortunately, because it is a misdemeanor, you'll need a lawyer. This is not a do it yourself situation.

You need to speak to an attorney, as pointed out by Mr. Dane. If you cannot afford an attorney, you need to ask the court to appoint the public defender. Do not speak to the police in an effort to try to talk yourself out of the situation. Your attorney is going to want to know whose car it was, and who the person was who placed the stolen registration sticker. You may have a defense, depending on your involvement with the placement of the stolen sticker.

You already got the point, you face a misdemeanor crime. However, your attorney should be able to use your proof that it was not your car, to defend against the charges. If serious about hiring counsel to do so, feel free to contact me.