The couple visit the legendary cemetery Pere-Lachaise and the city's historic catacombs
Gosling, 31, and Mendes, 37, enjoyed red wine and Argentine fare Friday night, before visiting the resting place of Jim Morrison, édith Piaf and Oscar Wilde, which is known as the City of the Dead.
“They were holding hands and there was a lot of tenderness between them,” an observer tells PEOPLE.
From Pere-Lachaise, they continued their grisly tour at the historic Catacombs of Paris, where visitors can go below ground to see the ancient stone quarries that make up the ossuary, which houses the skeletal remains of approximately six million Parisians.
Creepy … but trés romantique!