Yes, it is possible if the landlord stated in their ad that pets are allowed. You can also contact the landlord yourself and explain your particular circumstances and why you would like to rent with a pet.
If you have been renting a flat with your pet before, you can get a reference letter from the previous landlord stating that there were no problems during your tenancy.
Many landlords agree to allow pets in their flats when they are convinced that a pet owner is a responsible person who will not allow the animal to damage or destroy the property and items inside.
However, as a tenant, you must always remember that it is you who is ultimately responsible for your pet’s behavior.