Located in an awesome spot at the top of the Parc de Belleville with a large terrasse, this cafe is a top place to go to on sunny days. The terrasse provides a great view of Paris, including the Eiffel Tower, and drinks are reasonably priced.
Aside from the cheap drinks, O Paris also hosts live music every Sunday afternoon and does excellent brunches. The local area is really nice to visit and explore too, with the surrounding small streets filled with little boutiques and ateliers.
This spot is well off the beaten track, and the local area has a few street kids that might be a bit rough around the edges.