I strongly recommend taking the subway in Paris, the stations are beautiful and its a cheap and fast way of getting around. Keep your ticket until you exit your final station, you’ll need it to get out!
If you’re planning on going to Montmartre and the amazing Sacré-Cœur basilica the best stop is Pigalle. From there it’s a short walk and you will see great street art along the way, remember to look up, a lot of the public space take overs in Paris are high up on walls!
Place Pigalle, just when you get off the subway.
Lots of street art and some really good bars, like Dirty Dick on 10 Rue Frochot.
If you’re walking south I can really recommend walking on Rue des Martyrs, a street full of tags, cozy cafés and bakeries. I’ve tried several of them but my favorites are Sébastien Gaudard – Pâtisserie, on 22 Rue des Martyrs and Le Pain Quotidien, on 54 Rue des Martyrs where they serve the best Granola Parfait I’ve ever had!