Fuel smell

Greetings, forum members:

I have a 1999 Renault Clio, 1.6L single-point injection, that emits a strong fuel smell every time I fill it up with gas when it's parked.
This happens when the tank is more than three-quarters full. I'm worried because the garage is inside my house, and when this happens, the smell is truly unbearable (and I even think it's dangerous). I've looked under the car, but I don't see any obvious leaks. What could it be?

Thanks in advance.

Look if the tank vent is stuck and air enters when the fuel is spent. Luck....