Our apartment is very close to Bastille and the big square there has a huge assortment of pleasant outdoor cafés. One of our favourites is down the street a bit, La Cavetière. The food isn't particularly remarkable, being much like a hundred other casual brasseries. But the cooking is quite good and the menu choices are a bit more interesting and thoughtful than the usual. And they seem to have interesting wine choices every week.
What makes this place particularly nice is that it's sympa. The woman who works the outdoor tables is amazingly friendly. Our first time there she chatted with us about how she was glad we were there, how Americans never came to her restaurant, and wasn't it a nice day, and are you sure you don't want more wine? She speaks French very quickly but clearly and with the good will we understand each other. On our second visit a week later she recognized us, asked us how we'd been, patted me affectionately on the shoulder while taking our orders. That kind of genuine friendliness is not common in Paris, particularly for visitors, and for me it is very welcoming.