There is no real distinction between civil and criminal law in Amber. Crimes against persons and crimes against property are offenses against that person and the property's owner. The city is consider the Crown's demesne (other than the property directly owned by someone). With the exception of some offenses, such as treason, all crimes are generally considered to be against someone, who thus has the option of whether or not to take legal action. If that someone is unable to take action (because, for instance, they are murdered), it is usually incumbent upon their relatives to do so. Because of this, crimes committed against those of higher birth or greater wealth are generally treated more seriously.
Crimes committed in Amber City, in particular, fall under the demesne of the Watch. It is their job to keep the peace. They also investigate crimes on the behalf of either unidentified injured parties, or at the request of the harmed party. Most of what they deal with is petty theft, assault, and the like, among the lower classes. By and large, they try to steer clear of anything which might smack of involvement in politics, especially after Eric had the last Commander and much of his staff hung for pro-Corwin sympathies. The Watch is known to be somewhat corrupt, though individual Watch members vary in this respect. All citizens are expected to cooperate with the Watch, regardless of their rank, and the Watch will generally intercede if there is public violence, regardless of who is involved, although incidences involving the upper crust are more likely to simply be broken up — rarely does the Watch arrest a member of the upper crust unless they're fairly certain that the Crown will back them.
The penalty for most law-breaking tends to be some form of recompense to the injured party. Severe crimes, particularly those against the Crown, may be punished by tossing the offender into the dungeons, and may go as far as execution.
Justice for anyone other than the nobility is generally the domain of Amber's Magistrates, Crown-appointed justices who hear cases and make rulings. All cases where a noble is the one accused, capital cases, and any cases whose penalties involve more than a few days in the dungeons, are heard by the King directly.
Among the upper classes, most legal disputes involve contracts, or other instances where one party feels they have been wronged. When a member of the nobility is involved, or enough money is involved, these cases are heard by the Crown upon the request of one of the parties involved, although the King may appoint someone to deal with it rather than hear and rule on the case himself. Otherwise, disputes of this sort are handled by the Magistrates.
Most of the upper crust has a notable reluctance to bring such matters before the Crown. First, these cases are usually heard in open Court, which is potentially embarrassing, and may reveal secrets that one or both parties do not wish to have revealed. Second, the judgment of Oberon was capricious, and the judgment of Eric was often politically motivated. Justice was not necessarily a notable feature of such judgments. Consequently, two other methods for settling such disputes developed.
The first such method was vendetta — to wit, self-enacted revenge. The problem with vendetta is that it tends to spawn more vendetta, and has an overall destabilizing effect on the society. The upper crust has an avid desire, in most cases, to avoid vendettas. While the Crown essentially excuses actions committed in the pursuit of a just vendetta, there is the distinct danger that the Crown could rule at a later date that the vendetta was unjust, exposing those who were executing revenge to the Crown's punishment.
The second such method was arbitration. People may choose to have their disputes mediated by some ostensibly neutral third-party, agreeing to be bound by the result of the arbitrator's judgment. Notably, the Redressing Order of Clarity, an order of knight-investigators founded by Bleys at the end of Clarissa's reign as Queen, has a long and dignified history as a trusted group of arbitrators and skilled private investigators. This kind of extrajudicial arbitration has been useful not only for significant disputes between the nobility, which might otherwise go to the Crown for judgment, but also for what are essentially social disputes — matters of honor and the like. The parties involved typically agree to arbitration specifically because they do not want to have to settle the matter via vendetta, or bring the matter before the Crown. Once the parties have given their word to abide by an arbitration, breaking that agreement is considered dishonorable.
In some cases, a party has gone to the Order to request an investigation and the rendering of a judgment, but the other party involved in the dispute has not agreed to the arbitration. In these cases, the Order may still attempt to investigate. The success of such investigations varies; while tradition is that one tries to assist the Order in these cases, the Houses cooperate or not with individual cases for their own reasons, and the Order has no direct authority to order cooperation. After such an investigation, the Order may still render and attempt to execute a judgment. Legally, this is treated as if such a judgment were done under the terms of a vendetta. Socially, this is of varying levels of acceptability, depending on the the individual case. Historically, in instances where the case or the resulting vendetta has then ended up in the Crown's hands to deal with, the Crown has declined to prosecute knight-investigators for their part in rendering judgment, instead considering such things to be the responsibility of the noble house which requested their assistance. This has given the Order some protection, but does not remove the social and political (and legal) ramifications of such judgments.
The Order sometimes does contract work for the Crown. Most of the time, this is for the Exchequer, for whom they frequently serve in the role of hired auditors. However, the Crown sometimes contracts the Order to investigate a matter related to the upper crust, and to return a report to the Crown. In Crown contract cases, the Order still doesn't technically have to be cooperated with — but the investigating knights are usually able to obtain a Crown warrant for something if necessary, and the Crown is typically highly displeased by the inconvenience of dealing with the request, so the pressure to cooperate is accordingly much higher.
Both Oberon and Eric typically encouraged the upper crust to settle disputes amongst themselves. Bringing such cases to the Crown's attention often had the effect of ensuring that neither party was happy with the results, and was almost inevitably politicized.