It is illegal for your employer to fire you because you have filed a workers' compensation claim. However, it is not illegal for your employer to fire you for a legitimate reason, such as falsifying a job application.
The problem inevitably becomes one of proof. If you can prove that the stated reason for your termination (falsifying your application) is "pretextual" (or made up), and the real reason for your termination is because you filed a workers' comp claim, you can prevail and get your job back (and perhaps additional damages). If your employer prevails in proving that the real reason you were fired relates to your falsifying of the job application, the termination will be upheld.
Labor Code 132a prohibits an employer from discriminating against you (firing, demoting, decreasing your pay rate, etc) because you got hurt on the job, sought your workers' comp benefits or hired an attorney to represent you for your workers' comp case. This does not, however, protect you from being fired for any other reason. And, of course, this is hard to prove as they can always find another reason.
You may want to consult a good workers' comp attorney. There are plenty of good ones in Orange County. Find a good one here at www.avvo.com or at www.caaa.org. CAAA is the association for attorneys here in California who represent injured workers. Or you can call me for a referral.
If you are a Federal employee who was hurt on the job and have become disabled, the employer can terminate you and should terminate you after one year, but you will continue to draw time loss compensation until the weight of the medical evidence shows that you have recovered or that the disability is no longer related to the injury or until the employer provides you with suitable light duty work.
The answer would be a little different if you were already back at work in a suitable light duty job and the employer took away the light duty job for reasons that had nothing to do with the injury.