With more than 2.3 million listings, Airbnb is quickly influencing the travel industry.

The site connects travelers to “hosts” offering short-term rentals. Renters can make serious cash by renting out rooms, guest houses, or entire properties, and travelers get a comfortable place to stay for a fraction of what traditional hotels would charge.

However, Airbnb is also controversial. Critics note that Airbnb hosts aren’t under the same health and safety obligations as hotels, and because the Airbnb business model skirts regulations, it potentially deprives municipalities of much-needed revenue.

Many cities have introduced ordinances aimed directly at Airbnb and other short-term rental providers. Here’s a look at a few of the most notable cases.

1. Chicago, Illinois

In June 2016, the Chicago City Council imposed strict regulations on homeowners who offer their property for short-term rentals. Airbnb hosts would have to keep records on guests and pay a 4 percent tax to the city; one measure also limited the number of short-term rental units per building, making hosting more difficult for apartment dwellers.

The City Council planned to earmark the new tax income to fight homelessness. However, the regulations immediately resulted in a lawsuit from the Liberty Justice Center, which is based in Chicago.

While Mayor Rahm Emanuel didn’t comment on the lawsuits directly, he did give a cryptic clue regarding his office’s future plans for home sharing regulation.

“We’ve discussed today something new which no other city is gonna do, which we’re gonna try,” Emanuel said. “I can’t say it now because I’ve got to work something out. But I’m confident I will.”

2. Paris, France

Paris was one of the first major world cities to sign a tax deal with Airbnb, which required the site to pay the nightly tourist tax paid by all hotels in the city. However, that didn’t quiet Paris’s sizable hotel industry, which successfully lobbied the French government for more focused regulations.

“There is a revolution in the [hotel] industry, but the new actors simply have not been respecting the rules,” said Jean-Bernard Falco, head of AhTop, a French hotel industry group.

As a result of the new regulations, Parisian hosts must register their properties with City Hall and rent out their properties for no more than 120 days per year.

3. Barcelona

Barcelona’s city council, according to The Guardian, says that of the roughly “16,000 holiday rentals in the city… nearly 7,000 are unlicensed. Last year Barcelona fined Airbnb €600,000 for continuing to advertise unlicensed flats on its platform.”

The city council is trying to push back against rising rents, which have increased 23 percent in the past three years alone.

There are now 40 city inspectors investigating unlicensed Airbnb units. They’re threatening to fine the owners of the properties up to €60,000 per violation.

4. Reykjavik, Iceland

Tourism in Iceland is on the rise, and who can leave the country without visiting Reykjavik, the nation’s capital?

Airbnb’s rise has coincided with the growth of Icelandic tourism, and the two expanded together. Then city leadership decided that Airbnb wasn’t quite as welcome as it once had been. In January 2017, city legislators passed a law limiting apartment rentals to 90 days per year. After that, the owner has to get a hospitality license just like any other hotel.

Airbnb entrepreneurs are also limited to $8,785 in rental income every year. If you don’t follow the rules, you get raided—and you don’t want to cross the Reykjavik Metropolitan Police.

5. Amsterdam, Netherlands

Airbnb got a serious smackdown in the Venice of the North. The European city, which was one of the first to aggressively limit Airbnb’s activities through powerful legislation, put its money where its mouth was in October 2015. Actually, it was someone else’s money, and that’s kind of the point.

An Airbnb owner was ignoring rules that govern legal short-term rental in the city. So Amsterdam’s leadership hit him with a fine worth $26,000. After that, Airbnb owners started paying attention.

By February 2016, the city budget included a cool $1 million devoted to sniffing out illegal short-term rentals. After a year of investigation, the city charged $334,000 to one landlord and another agency who were operating Airbnb–like properties.

Long story short: If you own a house in Amsterdam, follow the rules, which dictate a maximum of 60 rental days at a time to no more than four people at once. The alternative could get expensive.

6. New Orleans, Louisiana

The Big Easy is now pretty hard for Airbnb owners.

The battle over short-term rentals in a gig-economy market came to a head during the 2016 Jazz Fest.

“This year, nearly 20,000 guests will stay in New Orleans during Jazz Fest using Airbnb,” crowed a marketing piece on the Airbnb website. They probably should have just stayed quiet.

When city leaders saw that figure, they decided to do something to make this new breed of hostellers compete on equal ground with the city’s oldest hotels. On October 20, the New Orleans City Council banned short-term rentals, at least in the city’s central party district, the French Quarter.

Everywhere else in the city, they decided to limit citizens to 90 days of renting their homes out per year. That, they figure, should cut down on the growth of short-term rentals.

7. Santa Monica, California

When you can’t get a hotel in Los Angeles proper, you might try for an Airbnb in nearby Santa Monica. That is, you might have tried that before June 2015.

That’s when the city passed laws designed to drive 80 percent of Airbnbs out of town. Why so harsh on Airbnb? It turns out that rental entrepreneurs were driving housing prices up. Some companies even bought multiple properties to rent them out as Airbnbs, so there were fewer houses for prospective homeowners to choose from.

The new laws will require any short-term renter to live on-site at the home in question during the entire length of a guest’s stay. The renters also have to register for a business license, and, perhaps most painfully, they have to pay the city’s 14-percent occupancy tax. So much for Airbnb in Santa Monica.

8. Berlin, Germany

Tourists visiting Berlin might want to check into a hotel rather than an Airbnb. In May 2016, the city passed laws that forbid homeowners from renting apartments to short-term guests.

Note that you can still rent out a room if you’re a Berliner with extra space. That’s totally legal, as long as the area rented doesn’t exceed half of the home’s floor space.

It’s best not to try running an underground Airbnb in Germany’s capital city, however. The city can charge fines worth up to $113,000, according to Conde Nast Traveller.

9. New York City

Even the Big Apple is working on diminishing the power of Airbnb within its borders. Governor Andrew Cuomo signed an October 2017 law that flat-out bans short-term rentals on sites like Airbnb.

New York City leadership is serious about this ban. They made it illegal to rent whole apartments for fewer than 30 days at a time. It’s even illegal to advertise rentals that violate these rules.

Violators don’t get away with a slap on the wrist, either. Two people decided to ignore the ban. Their case was completed in February 2017, when they were ordered to pay combined fines of $17,000 for a rental that didn’t go the required 30 days. Don’t mess with Cuomo, apparently.