Paris is generally very safe but here's what I wish someone told me about specific areas:

Avoid Châtelet-Les Halles after 10pm — Sketchy vibes and lots of pickpockets around Forum des Halles. Stick to Saint-Germain or Marais for evening walks.

Some Métro stations feel uncomfortable alone late. République, Bastille, Châtelet can be weird after midnight. Uber is €8-12 within central arrondissements if you're unsure about Line 1 or 4.

Highly recommend staying in 3rd, 4th, 6th, or 7th arrondissements. Safe, walkable, close to Seine and major attractions. I felt comfortable alone at reasonable hours around Rue de Rivoli and Boulevard Saint-Germain.

Trust your instincts always. If a street near Pigalle or Barbès feels wrong, head toward busier boulevards. Parisians are helpful — Ask women or families for directions to nearest Métro.