Cute little coffee shop, usually not too busy during the day. What makes this shop better than other hip third-wave spots is that the food accompanying the delicious coffee is pretty damn good. The menu is nothing out of the ordinary; expect sandwiches, croissants, and French café fare, but all well-executed.
The hexagonal floor tiles, old wood bar and stools and flowered tables make it a nice ambience, not too pushy but a mature fancy. It has those long wooden newspaper holders for instance, which immediately elevate the intellectual spirit of a spot even though they are purely aesthetic and serve no real function these days. Especially since no newspaper produces publications worthy of being draped elegantly as opposed to used as nail-clipping surface cover.
What to order: Petra has good coffee, any espresso-based drink here is suitable for a picky palate. Food-wise the croque monsieur was one that remained with me.