Help me find this place… (In Paris)?

I remember sitting at a nice garden in Paris. Directly facing me was a huge cathedral with a statue of a head resting in a palm (very Dali-esque), made of stone, on the ground (beside entrance).(It has been graffited with green paint)
The seating area was around some fountains, and the entire walk area was set out very strange… Parts was water, other parts was solid ground…. Like a jigsaw sort of thing… It’s very hard to explain….

I know we got off the metro at Les Halles (4), and it seemed a sort walk to here…. It’s definetely around the Latin Quarter….

The area was very popular, with lots of Parisians sitting around enjoying lunch…. It seemed kind of tucked away, and we were the only tourists…

Please help me! Thanks