Gasoline leakage

I have a 328i and from the beginning when I bought it over 2y ago I realized gas smell everytime I fill it up to the top inside of the car. Now I also saw/had some leakage right around the tank around the back tire, not even a little bit, it left a huge stain on the parking lot.. Did sb had similar problems or know what the problem could be?? I wanted to ask before tearing everything up while searching for the leak.. the smell and the leakage only happens when you fill it up to the top not if you just fill in a few liters