Have been using some of these city laws for awhile in my games. In most cases, there was never a conversation between DM and players, but what they found out during the game sessions. While I love to play impromtu style, in many ways, having the set rules make it easier in many ways as I am consistent in my rulings.
Towers: In Nyssian speak, a Tower is a Guild, or a group of professionals. Most cities are run and controlled by the various Towers, thru the use of laws and bureaucracies. Some of the most common types of towers include: Sollus (Light), Spell (Wizard Training) Sorrow (Mortuary), Silence (Martial Arts), Sword (Military Training), Trade, Paper (Bureaucrats), Merchant or Work. Most cities have a Tower Council that runs most aspects of the cities bureaus and offices, that elect their own on the High Standing Council (Towerocracy) if other ruling governments are not preeminent. Religious holy sites called obelisks are also on the Towerocracy listing. Rich or otherwise powerful Nobles may also get a seat on the Council. The Chair is very rarely a voting seat. Many groups may get multiple seats that represent their prestige and political power, so it is rarely doled out equally.
Taxes: Most travel taxes are paid upon entry thru the city gates paid on the wealth you are carrying, usually coins or other pieces of value. You pay once every two weeks, so entry more than once in that two week cycle will not cause additional taxes, to areas under the same entity. Rates are based on wealth, status, identity and role: Low (5%), Medium (15%), High (30%.) Travel tax is different than tax day; anyone in the city must pay on that day set amounts. Some Nobles may have Right to Travel, which prevents taxation on their horse or person. Magic is rarely taxed unless it is in the form of wealth, armor or items of status.
Gambling: By Tower. Small groups of card or dice rollers take and place bets at specific time and places, they often flee when Lawful groups appear not that they are breaking laws but do not want to be observed. Casinos are temples of Fatanus (Lady Luck), that are located in large communities. They take bets on almost anything, but sports is the most common. There is a fee to enter the Casino, and taxes happen as soon as winning happen, not when you leave the building, usually 10-15% flat charge but it can be more, often in proportion to the bet/risk percentage. Many have tables and specific types of games that are outright rigged, usually there is one or several tables that is completely open to actual fate . Minotaurs and Clockworks are the most common guards. Magic is often hampered by fields.
Jube: This is the most known and feared drug usually referred to as Spice, this is often called the Dream Spice. Most lawful societies allow usage of almost any drugs in medical or religious purposes, but some are restricted by class or nobility. It is rarely illegal to consume, but to create or transport usually is. Jubal is the Lord of Nightmares and Shadows; God of Addicts. They have no obelisks but hovels where they go to consume their dread. While most other types of activity can be covered by bylaws, jube isn't; it is tolerated, never spoken of in polite company and offered assistance by workers of Darras, the dutiful God of the Poor. Addicts aren't technically arrested for being addicts but being drunk or disorderly or causing other problems in public; the unspoken rule is don't arrest anyone if not causing issues for others.
Prostitution: By Tower, Open or Restricted. Open is the rarest type. Nearly every general fetish is accommodated. Payment varies from 20 to 2000 gp depending upon the desired service. Celestial or Devilish or Elemental entertainers are available in most large cities. Protection is guaranteed, so is discretion. Very few good-aligned religions and no neutral ones have rules against this type of vice.
Religion: Except in the largest cities, churches are uncommon. Faith is practiced near an Obelisk which is dedicated to a specific deity or ideal. Many cities have state religion where a particular church or cult takes a flat fee from all taxes paid. The Lawful faiths ones have a strict adherence of what must be done, as well as how and when it should be done.
Slavery: More accustomed to indentured service than slavery, most are captured due to debt, breaking laws or being captured in battle. Normally after a set period of service (20 years) they are granted freedom and settling rights. Children cannot be held enslaved, women and progeny are always freed at a child's birth. Halflings, Ogres, Cat-Kin, Gnolls, & Goblins are the most common beings held; Dwarves can be held as prisoner but very rarely as slaves. Many lawful and good groups oversee any slave in their area and use political pressure to free anyone they can. In Lawful Bound communities only Nobles with Right of the Chain may purchase slaves. Many communities permit Nobles to utilize slaves, but to a limit of three, five or ten outside of plantations. There may be no market square auctioning, or public lynching but it is seen by most as an evil, unjustice by most people.
Weapon Laws: Rapier, dagger or club can be carried by anyone, virtually anywhere. Some places have the same laws with the use of bow. Most professional adventurers have a license which usually costs from 5 to 50 gp for a year. Some locations have the Right to Carry; where Nobles can carry weapons without license.
Dueling: Most places have at least one day a week where anyone can duel without a witness. Nobles and Adventurers can duel as long as the other person also have the same right. It is not illegal to duel a non-noble or adventurer, but there will be questions if someone dies in a duel. Right of Honour gives Nobles the right to challenge those who have dishonoured them. Again, it is assumed that dueling is to the first three strikes, not death. If someone has a reputation for bloodshed, their actions are highly questioned, and legal experts often find a way to arrest or banish them.
Arena: Similar to Dueling laws except anyone that signs up for Arena fights has no recourse to get out of it later; death may occur though it is not specifically part of the deal. Gladiators are paid, given freedom from slavery or prison, or may be given other noble rights. It is never a one shot, often up to five duels must happen over a month or more. One of the few areas where magic combat openly occurs. Entry to the arena is usually between 1-4 s.p. and dueling occurs at least once a week. There is a continual standing of the top 50 warriors, who must defend their positions for wage and status.
Magic: There are few general rules regarding wizardly magic use. Some magic and users are heavily restricted, to the point where nearly every high level spell-caster stays away, whereas in Lyrria, the most powerful Wizards also virtually rule the entire nation. In most cities, clerics and their obelisks minimize the effect of potential spells as some types of spells (damage, cold, illusion, enchantment, etc) may be blocked. Also, in larger cities, higher level spells are blocked, so that 7th - 9th level spells cannot be cast within several miles. One benefit is that lower level spells, (0 & 1st, sometimes 2nd as well) are not lost when cast, so both clerics and wizard spells virtually guaranteed of being cast an unlimited number of times in cities.
Magic trinkets such as wands are often seized at the gate, to be handed back upon exit. Only weapons or armor are ignored, unless they are full of gems or valuable metals, then they are taxed at obvious value.
Nobility: Nobles represent those of power and stature, most often from wealth or past prestige. Many nobles have unique rights that citizens cannot normally obtain. While the first generation most often keep many of the rights of their parents, it does not descend a second generation unless it is earned. Depending upon the rules of the nation, Nobles have unique responsibilities. They cannot turn away from a request from an officer of the city or nation. They may not have entry fees to a city, but they have a yearly tax, on ALL of their wealth. They may be able to kill a low level commoner for insult but they cannot bad mouth the crown or it's officers.
Their magical rights are tattoos that show their capacity outside of regular laws. These must be shown if questioned. They are very difficult to fake.