As long as enforcement has not been stayed by a judge, a final judgment for the recovery of money or property entered outside of California in any federal district court, bankruptcy court, circuit court of appeals, or in the Court of International Trade, may be enforced in California by registering it in a federal district in California. (Non-final federal judgments cannot be registered unless good cause is shown or upon order of the court that entered the judgment.)
To register a final federal judgment, we file locally, a certified copy of the judgment with the clerk of the court that rendered the judgment. This local clerk then enters the judgment in the local district.
Unlike a state court-issued judgment, it does not have to be served upon the debtor; and once registered in the local district, the judgment has "the same effect as a judgment of the district court of the district where registered and may be enforced in like manner." (28 USC 1963).