Leasing or financing!!

Hello Citroen municipality, I have in another post, “C4 buy but where?”, write that I want to buy a C4. Now the dealer of my trust has made me several offers. (See above post). Well, since I also did not have a lot of experience in the new car purchase I once shorted myself with my parents and asked you about the advantages or disadvantages of leasing! Well and what should I say they totally discouraged me from doing so. But since I actually did not want to buy the I would like to listen to some other opinions. And so that you have an approximate picture of what’s going on, here are some basic data! C4 Limo. FAP 110 or FAP 135 White approx. 50,000km a year I would like to have your experiences in the Leasen and whether this is worth it at all for my kilometers and what the biggest disadvantages are when leasing. I thank you here already in advance.