@Seb2455
You should check your local authority in charge of that to get a detailed set of the rules in your region.
But in general, a tourist licence applies to dwellings which are habitually rented [for money] for periods of less than x-days (in some cases, it's 11 months, in other cases, it's less than 90 or 60 days - check your local laws).
The key thing is advertising. If you're listed on tourist platforms like Airbnb or Homeaway or Booking.com, and have no licence, they'll eventually find you, and then you could be subject to some serious pain.
Aside from a neighbour reporting it, advertising is generally how they'll find you. But without being listed on a platform (or other advertising), it's quite difficult to get bookings.
Besides, the purpose of licencing is to ensure that the dwelling offered meets basic safety and quality standards, and of course, to make sure you pay tax on the income.
Having said that, there's no law I'm aware of preventing you from having friends and family stay at your house, as long as there's no evidence you are making money from it.
Hope that helps.