@Deb29,
In France for example:
- being the owner you can rent any place less than 120 days per year legally (there is some exceptions). If you want to rent more you need a license. Many airbnb hosts don't have it, are illegal, and so as a guest you could be waked up at 6:00 pm by an inspector doing an investigation and the owner obliged to stop it immediately and to cancel all reservations.
- being a tenant, if your contract had been done after 2014 you can rent legally on Airbnb since you have the authorization of your landlord and since you don't get monthly more than your rent. If your contract have been done before 2014 you are automatically illegal, could be evicted and sued for a 25.000€ fine.
Each country have his own laws and regulations, and in one country things could be very different.