How can I remove the front bumper on my Citroen Xantia?

I need to remove the front bumber to get access to one of the fog lights. I removed three bolts that secure the bottom of the bumper to the car but cannot find out how the top of the bimper is attached. I guess there are some hidden bolts somewhere but i cant find them. The car is 2001 model petrol 1.8litre