Enforcement of laws throughout the city is not as consistent as it might be. The code of laws is well enforced in the Lord's City, the Merchant Quarter, and the North Ward. City guard patrols are pretty common and only the best of the guard is allowed to patrol these areas. Nobles have their own guards to enforce the law, as well.
Law enforcement becomes a bit more inconsistent from the Market to South Harbor. Patrols are less frequent and most of the guard are locals who may show favoritism. Some are even bribed by the local criminals. They are inspected enough that corruption is not rampant, though. It's more that there are a few bad eggs making the whole look bad. In addition, minor stuff like a drunken brawl will likely just have the guardsmen send the brawlers home to bed, instead of putting them in the stocks.
The Triangle is almost lawless. The local gangs protect people for a price. Brawls are fairly frequent and don't cause any alarm. Every month or so the city guard goes through the area, rounding up wanted criminals and dispersing the gangs. There is a hanging square in the Triangle that gets used a lot the day the guard comes through. A day or two after the guard leaves, everything returns to normal.
South Point and Cliffside are both well-patrolled. The merchants and the nobles do not want their industries impacted by criminals.
Hilltown has a small militia made up of local humans and halflings. They largely just settle matters amongst themselves. There is little serious crime, and any murderers or cultists are turned over to the city guard. A common punishment for criminals is to have a boxing match with the local boxing champion, Hugo of Hilltown (F3). He's a big man and a skilled boxer. He's only lost one fight in the last three years.
Tent City is periodically patrolled by the city guard, though most local enforcement is by the caravan guards that arrive with each caravan. The gypsies have their own enclave in the north side, and take care of criminals according to gypsy laws.