Say I write this:

I lived near Les Gobelins, which was a beautiful intersection full of trees.

Should it be this?

I lived near Les Gobelins, which is a beautiful intersection full of trees.

Les Gobelins is a neighborhood and a stop on the Paris Métro, and it existed when I was there and it still exists today. So is it is or was ?

Both are correct so long as you're consistent. Right? It's a style/mood thing, right? Right?